Consider your memories of 9/11. What time was it when you learned about the attack? Where were you? Who were you with?
By simply retrieving these memories, you are reinforcing how you remember this event. At the same time, you're pushing out more trivial memories, like what time you ate breakfast that day or what time you went to sleep.
But what happens when we communicate about these memories with others? Do our own recollections start to shift? Do our conversations shape how other people remember, too?