Your friend is a fucking con-artist or wackjob. Either way, I would distance myself.

If you're a skeptic you'll be of no use to her. Those kinds of industries rely on customers who are already believers.

What makes me laugh about people who believe they've lived past lives is their grandiosity. Most have either been a Native American warrior, a Titanic survivor or an ancient Egyptian pharaoh. It's never a cleaner for a supermarket in Birmingham.

Just say "NO"

Good question.
I'm always up for a fun experience. Past life stuff is nonsense to me but it might be interesting if I had nothing better to do. Amusing to see what they'd come up with.
I went to a mystic palm reading crystal baller once - she was way off and then got very upset when I informed her how badly she'd done.
They're usually better at projecting a nebulous future than detailing a real past.
Funny how that works.
"Tea reading gypsy fortune telling my dreams..."

Do not waste your time and be wary of that "friend". Once it becomes clear you do not share their neurosis they will turn nasty. I guarantee it.

Ask her if you can bring 20 Atheist friends with you ?

Regression therapy is pure, unadulterated horse manure. Anyone who risks it is simply being stupid.

I don't know....napping sounds kinda nice.

Go with it, and make up a story about how you and her were lovers, but then she murdered you, or something to that effect.

Tell her you are already familier with past life regression. Furthermore you did this for someone else in a past life and it just didn't work out very well.

This is similar to the notion that if skeptics would "just believe" they would see the light. And in a way, they are correct. "Just believe" is a deliberate suspension of disbelief, and in that environment, your biases and subconscious hopes and fears come to the forefront.

In general I would not do this, particularly if, as you say, your free time is both scarce and important to you. I have however indulged it on a few occasions.

Many moons ago when my first wife went through a brief period of flirtation with the charismatic movement, she dragged me to a Charles and Frances Hunter crusade. The "Happy Hunters" shtick involved bringing people to the "altar" for a "touch from god". This was a form of being "slain in the spirit". I thought, screw it, why not, and went forward to see what would [not] happen. I was lined up along with a couple dozen other people, each of us had a "catcher" standing behind us. The idea was that Charles would move along this line, filled with the power of the Holy Spirit, touch each person on the forehead, and they would swoon into the arms of their catcher. Each of them went down, one by one, until he came to me. He touched me and nothing happened. He touched me harder, pushing suggestively, and nothing happened. I looked at him, he looked at me, he shrugged and moved on. I was the Last Man Standing.

Why? Because I didn't engage in the group hysteria or play along with what was expected and I didn't care if I was the last man standing.

A few years ago my current wife and I, both atheists, were told about EMDR, Eye Movement Desensitization and Reprocessing, which for a time, was a semi-approved alternative treatment for PTSD, which my wife suffers from. One practitioner of EMDR stumbled on a modification of this that would, supposedly, in 80% of people directed in it, produce a so-called ADC, or After-Death Communication. For example a former soldier suffering survivor's guilt from his failure, in Nam, to save a mother and her child from a combat situation, had a hallucination that he met this mother and child on the "other side" and she gave him absolution and thanked him for trying to save them, hence, closure.

On a lark we made an appointment with this practitioner since he had an office near us in Chicago at the time, and he guided both of us through this series of relaxation and structured eye movements. The result, for us both, was zip, zero, nada, nothing (we were both fairly recently widowed at the time). Clearly we were both in the 20% of non-responders. I think it was a combination of really not believing there was an afterlife and not really badly needing more "closure" than we already had. I think these altered states really happen and the experiences are generally real (for some given value of "real" ) but they are not actual dead people speaking from the grave.

The common thread in all forms of such woo is a willingness to suspend disbelief and enter into a particular emotional / receptive state. If you expect to literally see dead people or be touched by god or whatever, a skilled guide can make the experience happen to most people's satisfaction; if on the other hand you expect to observe these things without preamble or setup or looking out of the corner of your eyes, you'll be disappointed.

I would definitely take a pass.

Take a nap - a more productive use of your time

If it ain't broke don't fix it. Don't let anyone mess with your mind just to practice up for their new business, Yikes!

It seems to work, that's for sure. I had some weird phobias all my life, such as an irrational fear of being killed if I looked at my bank account.

I decided to imagine I could see the past life where the problem first started, and went into meditation mode while riding in a speeding songtheaw (converted pickup truck bus) over the bridge to Ko Yo Island, Songkhla, going to work.

I pretended to be able to see that reincarnation, and in my mind I saw me, and my Jewish family-my father, grandfather and older brother hiding in the basement of a farm in Bulgaria just prior to WW ll. We were supposed to go to the river at a certain time where a boat would meet us with other Jewish refugees fleeing the country.

I was a 19-year-old boy, and had been working a job as a clerk in the nearby town so I decided to withdraw my savings before I left, so I risked a trip to town. One of the bank customers saw me and must have reported me to Nazi sympathizers, because my entire family was gunned down and killed on the way to the river that night.

When I "woke up" from remembering this I felt disoriented, because while living in the scene it was as though I'd been born in Bulgaria, and had the mindset of that era. So I googled the incident and found that even if we'd reached the boat, it didn't matter..the entire boatload of Jews was gunned down when they arrived at the sea harbor. Our government had secretly sold us out to the Nazis.

But, I was now free of the irrational fear of checking on my bank account, so I tried it again with other phobias I'd not been able to shake my entire life.
I hadn't really believed what I saw was real, but apparently it doesn't matter, for it to work.

Another issue was seeming to hear a baby crying in the back of my mind all my life, if I got quiet enough. I assumed it was because my mom didn't believe in picking up or touching babies, but when I pretended to return to the past life where the problem started, I saw my current sister, (who was, in that reincarnation timeline, my 14-year old Seneca Indian mother), a captive in a raiding band of young Creek warriors that had burned our village.

She gave birth to me on the trail, but the band leader (my current son in this timeline, but a warrior in that reincarnation. I learned that most people reincarnate in groups, and know each other, playing different roles each time) forced her to abandon me in a little rock hollow by the side of the trail. The crying I heard was me, the baby, who was left to die. So I corrected what had happened by imagining my mom returning, picking me up, nursing me and taking care of me in safety.

After that, I never heard the crying again.

I visited a number of past lives to clean up various problems I'd been having, and the relief was instant and permanent.

I have a long list of Kindle books of research on past lives, of children ages 2-6 who could remember details and conversations from past lives that researches could independently verify.

By the way, if you troll me, I'll just block you.

Take a nap and pretend you slept past your alarm

Past life regression therapy entails deep state hypnosis if memory serves me well. Anything can be implanted into your psyche under those conditions, personally I don't need or want anyone stirring up the cobwebs of my mind, I spent a lot of time and care creating that lair of spiders and snakes.

Do it.
It might be enlightening. Nothing really "spiritual" about the theory. Kind of like pseudo science.
Consider it supporting a friend and an enjoyable parlor game.

Here’s what I’d say to my friend: “You know me friend, I’m a huge skeptic. I’m willing to do this with you to help your business so you can be successful, but I might not play along as much as someone who believes in this stuff. If you think that’s still valuable, I’m in.”

Past lives is real. Have you not seen the documentary “defending your life” with Albert Brooks?

I would "take part in that nonsense" just out of curiosity. I'm more in the "what can it hurt" camp. You never know....