By default polls in Polly are open for 60 days. To close a poll manually, type
/polly close to get a list of polls you’ve created recently, or search for an older poll. Click on the
Close poll button to close the poll and prevent any further votes from being processed.
When authoring a poll, you can also choose to automatically close a poll at a specified. After you’ve started the authoring process, you can choose to schedule a poll from the drop-down menu:
Then pick the time you’d want the poll to automatically close.