There is no stored procedure to do this so far as I know. You can update system tables to rename Users in databases and Logins on the database. However, there are consequences. If a User owns objects, you'll need to change the object owner after changing the User Name. If you change the login name Jobs owned by the Login may not be accessible, logins in BAT files, packages, and applications will fail.
1) Rconfigure SQL Server to allow system table updates.
sp_configure 'allow updates', 1
go
reconfigure with override
go
2) to change a user name in a user database.
Update dbname..sysusers
Set name = 'oldname'
Where name='newname'
Go
3) to change the server login name
Update master..sysxlogins
set name='oldname'
Where name='newname'
go
4) reset the option that allows system table ad hoc updates.
sp_configure 'allow updates', 0
go
reconfigure with override
go
Terry L. Broadbent - Salt Lake City, UT
Home of the 2002 Winter Olympics (Feb 8-24)