What the host does about it
The clean answer is a second page. A follow-up session gets its own address, its own list, its own reminders and its own private access links; you do not extend or re-date the finished one, and there is no series view to switch on. The tidy habit is to have the next page roughly ready when the first one is sent out, so a late click can be answered with something real.
For the people who registered to the old one, a broadcast to that segment carries the replay, the slides or an invitation to the next date, and it arrives as email rather than as a chat message. Anyone who clicks an expired link and writes to you is a warm lead wearing a confused expression: reply with the next date, and put that name on the new page's list yourself if you can. A waitlist, incidentally, is only useful while the room exists โ an overflow list on a finished session is a promise you cannot keep.