Override constraints

I have to change someones username in my database in a couple of tables. When I try to make any changes, I get an error that there is a constraint. Is there a way to make the changes without removing all the constraints then replacing them?
Thanksheh. sucky. take a look at your constraints to see if they're really necessary. Or follow the correct insertion plan so the contstraints don't block you.

if it weren't 2000, I'd say SET DISABLE_DEF_CNST_CHK, but that's no longer supported.