Unbend (verb)

1. To straighten or make straight again.
2. To relax or become less rigid.

Origin:

From un- + bend.

Examples:

1. She unbent her stiff legs after sitting for a long time.
2. The metal unbent when it was heated.
3. He unbent his stiff back after a long day of work.
4. She unbent her attitude and became more approachable.
5. He unbent his stance on the issue after hearing the other side.