I have a client that wants her board's polling system to allow members to change their mind. This allows for one to vote on a topic in the beginning, and then be swayed by the conversation. One's vote only counts once like it is created now, but they can change their mind if they change their mind.
My client is still asking. If this is an easy mod to write, we would pay to have it written.
When you post a new poll, just make sure to check the option for allowing the member to change vote.
Look at the image below for an example:
(http://img88.imageshack.us/img88/783/untitledvc0.png)