Can reward tickets be refunded or endorsed to other airlines?

Skywards Flex Reward tickets can be refunded for a fee of US$50.  Skywards Saver Reward tickets and Partner Airline reward tickets can be refunded for a fee of US$75.  Note that once issued, reward tickets cannot be endorsed for travel on other airlines.

What are the differences between a Skywards Saver flight reward and a Skywards Flex flight reward?

Can I combine Saver rewards and Flex rewards?

Can reward tickets be refunded or endorsed to other airlines?