What should be done in the event of being prevented from performing Umrah before reaching the Miqat due to the unavailability of alternative flights to return to Egypt, followed by a later return to Dammam with the intention of performing Umrah again?

Ihram is the intention to enter into the ritual. So, whoever wears the clothes of Ihram but does not intend to enter into the ritual is not in a state of Ihram. As for whoever intends to enter into the ritual, they have become a muhrim (one in a state of Ihram), and their Ihram has commenced, even if it was before the Miqat. It is not possible to exit the state of Ihram except by completing the ritual, or by exiting it if a condition was stipulated and that condition was met, or by being prevented (from continuing). And whoever enters Ihram but does not perform 'Umrah must wear the clothes of Ihram and avoid its prohibitions until they perform 'Umrah.