marching orders

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun plural Orders to move on or depart.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun Instructions for action.
• noun idiomatic Dismissal: an instruction to leave.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun (informal) a notice of dismissal or discharge
• noun an order from a superior officer for troops to depart