HotSpot: Update a DHCP Variable When a User is Connecting to HotSpot

Hi,

I have two Wi-Fi modems that connected to MikroTik for HotSpot in two rooms. One of them has “myRoom1” agent circuit id and the other has “myRoom2”.
When a user connects to modem1, the “DHCP Server Agent Circuit Id” gets a value of “myRoom1” and expires after an hour.
If the user disconnects and go to room2, then he/she can connects to modem2, but the DHCP circuit id is not updating and has the value of “myRoom1”.

How can I update a DHCP variable, when a user is connecting to HotSpot?

Thank you in Advance.