Originally Posted by
WineCountryUA
Day of travel, the carrier that creates the problem is responsible. UA is not involved and would be of little help as UA does not have service to MLE.
Congrats on the award ticket
And for the sake of any future curiosity: This is an IATA rule applicable to virtually any interline itinerary regardless of cash or award, alliance or non. It's one of the key benefits to booking travel on a single ticket rather than "doing it yourself" by combining multiple separate tickets.
That said, while the late delivering carrier is responsible for fixing the issue, UA as your (travel) agent in this case may be a helpful last resort -- but only if the late delivering carrier fails to resolve things expeditiously.
See IATA "Interline Considerations on Irregular Operations (IROPs): Guidance Document for Airlines" @
https://www.iata.org/contentassets/e...25june2020.pdf
IATA Resolution 766 (Interline Passenger Reservation Procedures) states that whenever a passenger arrives at an interline point too late to make his connection, it is the responsibility of the delivering airline to cancel any continuing space that cannot be used and rebook the passenger as necessary.