How do we get informed that the nameservers change has been completed?

The “.cy” zone file reload times (UTC/GMT) are: 00:00, 03:00, 06:00, 09:00, 12:00, 15:00, 18:00, 21:00.

If you want the change to be made immediately, you perform it close to a reload time.

To check if the change has been applied, connect to the Automated System at https://www.nic.cy  and follow the procedure found here.