There is a labyrinth of mind-numbing rules, policies, fees and restrictions related to changeable airline tickets. The reliability is not worth the legwork + option premium. I would rather face the consequence (give up).

— based on https://www.tripbase.com/flight-search/flights-with-changeable-dates/

Changeable tickets are available through almost all airlines and online travel agencies. Some “options” are issued by airlines; others are issued by third-party sites.

Without the option, you will most likely be charged by both the airline and the travel agency. Typical fee is too high to deserve my time, so I would rather give up when I can’t travel and have no option.