back out

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

• verb To reverse a vehicle from a confined space.
• verb idiomatic To withdraw from something one has agreed to do.
• verb idiomatic, computing To undo a change.

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

• verb make a retreat from an earlier commitment or activity
• verb move out of a space backwards