SQL Server/T-SQL Tutorial/System Functions/sp RevokeDbAccess
A statement that revokes access to a database for a SQL Server login ID
<source lang="sql">
EXEC sp_RevokeDbAccess JohnDoe</source>
A statement that revokes access to a database for a Windows user account
<source lang="sql">
EXEC sp_RevokeDbAccess [Accounting\SusanRoberts]</source>