Is a hady obligatory and how does one exit the state of ihram for someone who intended 'Umrah, stipulated that if she was able, she would perform the 'Umrah, and if not, she would not perform it, and then she was unable to perform it?

The pilgrim does not exit their state of ihram (definition) merely by wearing sewn garments or changing their intention. They are only released from ihram by one of three matters: completing the ritual, performing tahallul (release) after making a condition and its cause arises, or being prevented from continuing (ihsar). If the questioner stipulated at the time of ihram by saying: "If something prevents me, then my place of release is where I am prevented," then she may perform tahallul and nothing is incumbent upon her. However, if she did not stipulate, she cannot perform tahallul except by completing the Umrah (definition). If she is unable to walk, it is permissible for her to perform Umrah while riding. If she cannot do so, she remains in her state of ihram until she is able to perform Umrah. If that becomes impossible, she performs tahallul like one who is prevented (muhsar) by intention, slaughtering a sacrificial animal in Mecca, and then shortening her hair.