Hi Chris,
Please test for null or empty value in the field using if function in the expression. You could try this:
if(empty(triggerOutputs()?['body/ReturnTravelDateTime']),'Not Available',formatDateTime(triggerOutputs()?['body/ReturnTravelDateTime'],'dd/MM/yyyy'))
here, if ReturnTravelDateTime is null or empty, the expression will return 'Not Available'. You may modify this in the expression as per your need.
If this helps & solves your problem, please remember to give a 👍 and accept my solution as it will help others in the future.
Thanks
