I can only speak from personal experience ... to explain how my mind works from my own personal experience I like to use computers as a metaphor. In fact the way google works is a direct reflection of how the human brain functions.

The google search engine just sits there waiting, when I type something into the google search engine it comes up with results at lightning speed. How did it do it? It searched in it's data base, ran it's programs, applied it's algorithms and out came the results. These results of course depend on it's memory banks, specific programs and algorithms. It's regularly updated, files, programs, algorithms are deleted and new files, programs and algorithms are contantly added.

My mind works in exactly the same way and has been ever since I was born. Something appears in my inner space in the form of thoughts, emotions, bodily sensations or more commonly something appears in my outer space(my story space more commonly known as the physical world) in the form of signals through my physical senses. In a flash my mind runs it's programs, searches it's memories and out pops a result that I become aware of, however in my mind the result is a story that's told with thoughts, emotions and bodily sensations.

And my mind has been refining it's programs and updating it's memories ever since I was born. So can I actually rewrite my past, create new memories, modify the memories already in place?

Afterall that I've just said the answer is obviously "Yes"

? Start by putting a whole lot of money into your bank account but do like 15 years ago so the IRS isn't suspicious. Then, got to the nearest hospital & go down the the rehabilitation wing. See all those people missing limbs or in a wheel chair? Tell all about reimagining your past.