En SQL_2000 es con sp_changeobjectowner pero como ahorita no tengo a la mano el SQL 7 no se si en él sirva.
En la documentación del SQL_2000 viene lo siguiente sobre el sp mencionado:
Cita: sp_changeobjectowner
Changes the owner of an object in the current database.
Syntax
sp_changeobjectowner [ @objname = ] 'object' , [ @newowner = ] 'owner'
Arguments
[@objname =] 'object'
Is the name of an existing table, view, or stored procedure in the current database. object is nvarchar(517), with no default. object can be qualified with the existing object owner, in the form existing_owner.object.
[@newowner =] 'owner'
Is the name of the security account that will be the new owner of the object. owner is sysname, with no default. owner must be a valid Microsoft® SQL Server™ user or role, or Microsoft Windows NT® user or group in the current database. When specifying Windows NT users or groups, specify the name the Windows NT user or group is known by in the database (added using sp_grantdbaccess).
Return Code Values
0 (success) or 1 (failure)