Originally Posted by Anonba

Ticket validity is adhered to strictly, so unfortunately you arent going to find a way round this without making multiple changes.

If you make a change now to a date within your current ticket validity (date in December), the reissue date is going to be a date in September. Once this is done your new ticket validity will be 1 year from the reissue date aka September and you can then change to dates in May you want.