Removes a security account from a SQL Server role in the current database.
sp_droprolemember removes a member from a database role by deleting a row from the sysmembers table. When a member is removed from a role the member loses any permissions it has by membership in that role.
To remove a user from a fixed server role, use sp_dropsrvrolemember. Users cannot be removed from the public role, and dbo cannot be removed from any role.
Use sp_helpuser to see the members of a SQL Server role, and use sp_addrolemember to add a member to a role.
The following example removes the user JonB from the role Sales.
EXEC sp_droprolemember 'Sales', 'Jonb'