No one can change the past, but any stuck emotional charges can be drained or abreacted out of the mind. Abreaction is a psychiatrist's term for the therapeutic discharge of old, and obsolete emotion. This is commonly in the form of laughter or tears, but not necessarily so. From time to time, past life incidents may surface. If one wishes to be a science fiction writer, then keep a similar book to the one used for the things one has done in this lifetime.
Past lives are prone to many problems.
People tend to remember, not their own past lives, for these were too uninteresting, but those of their heroes. Thus in Britain, the top of the reincarnation hit parade, is Admiral Lord Nelson, the great British sea hero of the Napoleonic wars. If one wishes to remember past lives, then one must be prepared to take responsibility for those past lives. The other downside is that one can get bogged down trying to get the detail. If one develops enough responsibility, past lives will appear of their own accord but one may lose the detail.