go back on
Fail to honor
To go back on something is to break a promise, reverse a commitment, or fail to honor an agreement: He went back on his word.
The phrase implies betrayal of trust—you had committed to something, then retreated from it.
She said she'd help, but she went back on it at the last minute.
renege
Break a pledge
violate · dishonor · backtrack · abandon · disown · repudiate · disavow · abjure · forswear · recant
promise fulfillment
go back onkeep
Retain or fortified tower
honor · fulfill · follow through · uphold · stand by
back, gone, going, backward, backing, backed, backs, go back