A recollection letter is something that is written down so that you will remember it later on in life. This helps you recall past occurrences and will help you recover the… memory. (MORE)
It's a theory of knowledge developed by Plato and/or Socrates in Plato's "Phaedo" and demonstrated in "Meno." The short version is that our souls, being… immortal, have lived countless lives before us, and have gathered all the knowledge that could ever be. So, in our lives, we gain knowledge not by learning, but instead by recollecting what we already know in our souls. (MORE)
To write a recollection letter, be thankful for what she/he done. say you are sorry for all the wrongs you have done, and wish him/her a well for the rest of his/ life.