I used my Etihad miles for an award seat on Oman Air from MCT to COK on the 24th. However, due to the current situation in LHR, I want to change the date (I am in NY and changed my JFK-LHR-MCT booking on BA to another date as advised by BA). Both EY and Oman-Air are saying date changes are not permitted (my ticket is booked in W class). Is this true?

When I make the booking, I was told only date changes are permitted. Is there anyway to make this happen?

Thank you.