"To remap the button" means to change the function or assignment of a specific button on a device or controller to perform a different action or task. Full definition
While you can't remap the button by just using your phone, apps like BxActions, or BixRemap can get the job done. (androidcentral.com)
That's the word from XDA Developers, a developer - focused site, which was tipped off to the updated Galaxy S8 software by a developer working to update his app to support remapping the button on Samsung's newly unveiled phone. (tomsguide.com)
Even if that is the case, why now allow the player to just remap the buttons as they see fit? (blog.us.playstation.com)