British English has many phrases for changing a plan without drama.
Back to the drawing board: The plan has failed, so we start again.
To change tack: To try a different approach. The phrase comes from sailing.
To roll with the punches: To adjust to setbacks instead of fighting them.
To make the best of a bad job: To get the most out of a poor situation.
Needs must: The situation forces a change, so we accept it.