Unbend

verb

1. To remove a bend so as to make, or allow to become, straight

   "to unbend a bow"

2. To release (a load) from a strain or from exertion; to set at ease for a time; to relax.

   "to unbend the mind from study or care"

3. To unfasten sails from the spars or stays to which are attached for use.
4. To cast loose or untie

   "Unbend the rope."

5. To cease to be bent; to become straight.