Can a body part which may reasonably br presumed to have the status of erwa for a particular woman ever lose that status?
Some examples are if a woman is widowed or divorced can she legally uncover her hair? Some rabbis issue heterim for a shiddukh to take place.
If a single woman takes on covering her hair, can she after many years uncover ot again even with hatarath nedarim?
If a woman takes on a full coverage dress code, can she start showing forearms or leg below the calf in public?
How permanent is this status of erwa?