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

Do I earn the same Miles Accelerator bonus if I have purchased a Skywards Flex or Skywards Saver fare?
Why should I buy a Skywards Flex fare when a cheaper Skywards Saver fare is available?
What are the differences between 'Skywards Flex' and 'Skywards Saver' fares?