Two users having the same ID

Hi,

I have this problem with one user. He forgot his password. Therefore I recovered his password.

As and when he tried to recover his ID in his Notes client the ID prompted different name.

When I checked in the PAB it seems like these two users having the same ID filename. How am I going to solve this? Is it by simply changing the ID name stored in his PC and also his profile in PAB

Pls help