Allow the ability to change or rescind a vote

Ideas evolve as they are discussed. It is likely, and desirable, that persuasive arguments result in the change of the votes of the participants. Presently, we cannot change a vote or rescind a vote once cast.

Use Case 1: I successfully lobby my point of view and you want to change your vote from Down to Up on the basis of the discussion.

Use Case 2: The discussion has wandered off-topic and no longer represents something I am interested in. Allow me to rescind my vote and remove my association with the idea.

Use Case 3: A discussion results in the consensus that the idea was a bad one. Allow the participants to kill the idea by reversing their individual votes to Down.