Your vote automatically closes when it reaches its scheduled end time or when all voters have voted. However, you can also manually close your vote:
Manually Closing a Vote on the Dashboard
go to your Dashboard
find the vote you want to close
select Close from the Actions dropdown menu
a warning message asking for confirmation will appear; select OK to close the vote
Manually Closing a Vote on the Results Page
go to your Results page
select Close from the Actions dropdown menu
a warning message asking for confirmation will appear; select OK to close the vote
Cancel, Early