Correct me if my assuptions are wrong!
I understand you are trying to change the structure of a SQL Server System Table called "Sysdatabases" that resides on the Master database, if that is the case I recoment you not to make that cjhange since it may crash your server.
Or you are trying to make a change to a user Table on a user databases that retains a list of the databases on you server, that I recoment you to use "ALTER TABLE" you can read all about on BOL search for "ALTER TABLE" AL Almeida
NT/DB Admin
"May all those that come behind us, find us faithfull"