Once you open a pull request, ChaosBot will give it X seconds (where X is determined by github_api.voting.get_voting_window) before collecting votes. During this time, you should let people know about your contribution, so that they may vote for it and ensure your hard work gets merged in. If you do not wish for ChaosBot to consider your PR for merging just yet, add "WIP" somewhere in your PR title. Remove it when you're ready for voting.
You may change your PR at any time without losing votes, but keep in mind, any new changes will reset the vote window for additional time.
At the end of the voting window, ChaosBot will review the votes, and if your PR crosses a threshold, your changes will be merged in. If your changes are not merged in, take the time to consider the feedback you received, and create a new PR with changes you believe people will be willing to vote for.