MyBB Codes

I know that we can't undelete the user. He has some post. The user has been deleted. Example:
http://forumvilag.com/Tema-Goldi-bemutatkozasa
You can see author name and "unregistered" group.
After he registered in forum. And he want the old post.
I like add the old post to new user. Example I can add "deleted Account name", after the program searching the all post in unregistered group posts with this name. And I can add the "Destination Account". After the script add all old post to new user profil and recount post number.
Can you make this plugin? The old name is in adatbase with unregistered group.

If you primary intention is to "undelete" a user that was deleted by mistake. It would be easier to recreate this exact same user and assign him the same Uid and Username values. The posts would then be related to him again!

If you just want to be able to merge his old posts to someone else this is another story...

There was one plugin, but I dind't find. Perhaps has been deleted.
There was new options in post in Moderate button. I can edit author name and the script set her Uid.
Example I edit post and I can edit the username. The programme is search the registered members uid and rename to new uid. This is admin permission.