Slido is available in Webex Meetings and Webex Webinars. You can use Slido in Webex Meetings on version 41.6 and later sites, and in Webex Webinars on version 41.9 and later sites. Slido polls and Q&A in webinars are available for up to 10,000 attendees, while quizzes are available for up to 5,000 participants.

Participants can still vote for questions after you close the session.
1

During the meeting or webinar, go to My interactions, hover over the Q&A, and then click the red lock icon.

2

Confirm the action by clicking Close Q&A.