I have a player with worldmodes.modes.* and they can't be changed back from creative. They don't have any autoset permissions, it just says "The game mode change was cancelled." I can't get anything to work. Not even I can change it.

Do you use any other plugins that may be enforcing game modes? Can you post your permission configuration, please? Also, what permission plugin are you using?

The fact that other players with the same rank can change would indicate that this player has a player-specific permission set. Can you please check if the player actually has the worldmodes.modes.survival permission in that world. I believe the command is something like

/pr <username> w:<world> has worldmodes.modes.survival

You can also check the Permissions plugin folder and its subfolders to make sure that the player doesn't have special permissions set.

I'm using Permissions. All of the other users of the same rank can change. Just not this one user. I uninstalled all GameMode plugins except this one. My permissions for world: http://pastebin.com/GpVmU14N

It was an error in permissions. It should be "worldmodes.mode.", not "worldmodes.modes.".

ahhh... I should have caught that. Glad you solved it.