Seeing past lives as in other people's? I'm not sure if that's what you mean. Through meditation people have been known to see what is believed to be past lives, but true past life reoccurrences are achieved by the one who's past life it is. To put it in simple terms in most cases you'd see your own past life. I say in most cases because I can't rule out the possibility that someone with psychic abilities couldn't have a vision of your past life or that there is some kind of tarot card reading that could reveal information about your past life, but as I said as i understand it people normally receive information about their past lives through meditation. Past life recollections aren't common and I assume aren't the easiest thing to achieve as you are viewing memories unrelated to your current life. I find the concept of past lives intriguing but if I am reincarnated do I want to discover I was possibly the ancient version of a plumber in my past life? Sorry returning back to the seriousness of your question (no offense meant) I personally have no experience in past life regression or recollection. I wish you all the luck in the world with your desire and hope someone else can be more helpful.
O it is possible to know if someone has a past life I have a friend that has a past life and has helped another friend of mine with awakening his past life he is trying to help me awaken my past life but it won't let me