If something happens to a person in a state of Ihram that prevents him from performing the Umrah and he forgot to make the condition during his intention for Ihram, what does he need to do?

A. If it is possible for him to wait until the source of obstruction is alleviated then to
continue, then that would be ideal. If he is unable to wait, then he falls under the ruling
of one who has been blocked or prevented from completing Umrah and the following
Qur’anic verse pertains to him: “And complete the Hajj and ‘umrah for Allah. But if you
are prevented, then [offer] what can be obtained with ease of sacrificial animals.”- Al
Baqarah (2:196)

B. He is required to sacrifice a sheep and to give it to the poor people of Makkah
and to shave or shorten his hair then exit the state of Ihram. Then he needs to
repeat the Umrah in the near future or whenever possible.