change from microsoft acount login to local account login

Of course I know how to do this.  But I have run across and situation that has presented a problem.  A user upgraded from windows 7 and kept his local login.  Later when attempting to search, the computer asked for a password he typed in his Microsoft live password.  then after logging out of computer he now had a Microsoft account login.  In attempting to change back to his local account login he is required to create a new login name.  When trying to use his old login id it give an error that it is already in use.  I assume that if he creates a new user id that this will create a new user on the computer and he will have to move all of his data to new user.  Why can we just convert the user account back to a local login.  

So the account id was User.  Then it became User@microsoft.com.  But when you look at the users folder on the c: drive there is only the one account: User.  What is needed is to be able to convert the Microsoft login back to local while it logs into the same User account as before.

Also odd is the when looking at other sign in option is says you have to create a password to use these options but he did login with a password because he had to as required by the Microsoft account login.