Let me combine two (or more) memory node...

Let me combine two (or more) memory nodes. The app assigned "user" as my username, but my name of is Niki. I informed it of this, and it created a second node titled Niki, unrelated to any of the other nodes (except that I have a dog). I can't replace the name User with Niki because it says that node already exists. I can't even see the Niki node anymore. Help!