fall back on

fall back on or fall back upon  {v. phr.}

1. Сдавать позицию.

The enemy made a strong attack, and the soldiers fell back on the fort.

2. Оказывать помощь; помогать в нужную минуту.

When the big bills for Mother's hospital care came, Joe was glad he had money in the bank to fall back on.

If Mr. Jones can't find a job as a teacher, he can fall back on his skill as a printer.