[Pls ignore]changed value of a unique key, still shows duplication error.

[abduraooft]

Hi,

I've a user table in which the username is indexed with unique key.
For some reason, I've to allow a set of users to register again using the same usernames that were used by them before,

So I just updated their current usernames by appending and '_old' to their current value. But it says Duplicate entry '*****' for key 1 when I try to register withe their old usernames.

How can I make it to work as I indented ?

Thanks.

Nevermind :I think the problem is with another table in the process