When hosting a meeting, you have the option to move attendees to the waiting room at any time during the meeting. This feature is only available if the host enabled the waiting room option upon scheduling the meeting.
The waiting room feature allows the meeting host to control when an attendee can join the meeting. As the host, you can admit or deny attendees individually, or hold them in the waiting room to be admitted all at the same time.
Note: Once you move participants to the waiting room, you can admit them back.