A lot of these are wrong. They are 'grasping at straws' to make them fit. In what situation does the word clip actually mean to unclip something? A possibility could be clip to put things together, but to clip as in to trim, but that isn't an antonym to be specific, it is more of an alternative use.
The correct words are resign (which is to step down) and re-sign. The hyphen is important.