If I purchase a 'Skywards Flex' fare, does that mean it will be free to change at any time?

Not necessarily. A Skywards Flex fare is related to the Skywards earning structure. Emirates fares have different rules and conditions depending on many factors - please check the fare rules and conditions when you purchase your ticket.

Related questions

How do I identify a Skywards Flex or Skywards Saver fare after I purchase a ticket?
How do I identify a Skywards Flex or Skywards Saver fare before I purchase a ticket?
What are the differences between 'Skywards Flex' and 'Skywards Saver' fares?