I have found a fantastic Z fare ( will disclose later). However, I'm really confused about the restrictions for Z fare. Based on the fare rules, changes and cancellation are allowed at any time. However, United rep said generally it will cost me $500 to make changes. However, the fare rules don't mention anything about the change fees, nor the fare rules say anything about ticket validity period. My question is: Should I assume the ticket validity period is 1 year from the booking date? Should I trust in the fare rules or the rep? assumed the ticket expires in 1 year, Is it possible to change my return flight to a date beyond the expiration date? Thanks!