Go back on and Pull back

Go back on verb - Fail to fulfill a promise or obligation.

Pull back and go back on are semantically related in back off topic. In some cases you can use "Pull back" instead a verb "Go back on", when it comes to topics like renege on.

Pull back verb - Pull back or move away or backward.

Go back on and pull back are semantically related in back off topic. Sometimes you can use "Go back on" instead a verb "Pull back", if it concerns topics such as renege on.