In the Gates of Arkham expansion, when you become a member of the Sheldon Gang or the Silver Twilight Lodge, is the membership something you can choose to give up at any time? Or does one have to lose the membership through a game mechanic such as becoming a member of the Sheldon Gang when you are already a member of the Silver Twilight Lodge?

Thank you.

You cannot get rid of the memberships unless a specific effect says so (for example, becoming member of another society)

Thank you.