back off from something—withdraw from smth. one has promised or agreed to do:
- Schultz continues to resent Syria’s backing off from a peace agreement.
back out of something—1. move out of smth. backwards:
- He slowly backed out of the room keeping his eye on the angry dog all the time.
2. = back off from something:
- Buying at auction can be risky, in part because buyers can’t back out of the sale.