The short answer is that there is not much you can do once such a directive has been issued. However, you can take steps to make such a difficult request less likely in the first place. Provide your supervising officer with a current copy of your work schedule. Make sure that you can prove you have given it to him/her! This is best accomplished by faxing a copy of it and keeping the confirmation sheet. Do not ask for a signed receipt from the officer. This will put him/her on the defensive.