Make someone a co-host Open People, open the person's menu and choose Make co-host. The host can also Revoke co-host, Make presenter, Make moderator or Transfer host. By default co-hosts can mute, stop video, remove people, admit from the waiting room, spotlight and manage sharing, chat, polls and Q&A. They can't act on the host or transfer host, and can't lock the meeting or end it for everyone unless the host allows it in Host Tools. Your plan sets how many co-hosts you can have.
If the host reloads or drops The host keeps the role for 30 seconds, so a page refresh or a short network drop doesn't hand it to someone else.
When the host leaves Choose Leave meeting (assign new host) to leave without ending the meeting. When there is no host any more (after those 30 seconds), the co-host who joined earliest becomes host. With no co-host, the person who has been in the meeting longest becomes host.
The meeting owner gets host back When the owner rejoins, anyone who became host automatically while they were away goes back to co-host. Where the owner's own menu shows Claim host (you own this meeting), the owner can take the host role at any time, and can use Remove host role (make co-host) on another host. Someone the owner chose with Transfer host keeps the role.
To end the meeting for everyone, use End meeting for everyone (in More, or in the Leave window).