Is there a way to edit a poll?

Yes. It is restricted to super moderators and administrators in most boards, due to potential for abuse.

If I have created a poll, and it has closed, could I possibly change it, seeing as I am the creator of the thread?

Me too , i want to delete a thread poll , is that possible ?

Contact a super moderator, with a link to the thread, explaining why you want it changed.

Alternatively, report the first post of your thread, explaining why you want it changed and what you want it changed to. This may be faster.

We cant make multiple polls in the same thread right?

Correct.

ah! right. its a poll so it should only have one question. I was thinking of a survey! XD

If you edit polls, what will happen to the votes?

That's where potential for abuse comes from. When an smod edits the poll, they can also edit the vote counts. There are ways to obtain the original votes, but it's annoying to have to do that. This is why normal users and local moderators generally cannot edit polls.