How to Migrate Ubiquiti Unifi AP to a New Controller

How to Migrate Ubiquiti Unifi AP to a New Controller
Prerequisites:
    1.    determine the IP address of the access point, you can scan the network looking for it
    ▪    nmap 192.168.42.0/24 |grep Ubiquiti -B 5
    ▪    nmap 192.168.42.0/24 -p 22 -oG - |grep open
    2.    be logged in to the new Unifi Controller website
Steps:
    1.    ssh into the access point using the admin credentials the current controller software uses (typically “admin” for the username and whatever password is assigned). For example: ssh admin@192.168.42.71
    2.    reset the AP to the system defaults by running “syswrapper.sh restore-default”. The AP will  then reboot.
    3.    about 20 seconds after reboot, ssh into the access point again using the ubiquiti default username: “ubnt” and password: “ubnt”.
    4.   after logging in type “mca-cli” and hit Enter
    •    at the UniFi# prompt type “set-inform http://<ip address or domain name>:8080/inform” and hit Enter
Browse to the Ubiquiti Unifi controller website - https://<ip address or domain name>:8443. Before running the set-inform command, it should show 0 pending devices: but afterwards, it should show 1 pending device:
Click on the link of the MAC address of the pending access point to adopt the device and click the adopt button.
The state of the access point will change to “Adopting”. Wait until the state changes to “Disconnected” before moving on to the next step.
After the state shows disconnected, wait 1 more minute and then go back to your ssh session and run the set-inform command again
    •    set-inform http://<ip address or domain name>:8080/inform
    •    type “exit” to leave the mca-cli utility
Monitor the progress of the rest of the migration from the controller website. Within seconds of running the set-inform command the second time, you should see the status of the AP change to “Upgrading” (if a firmware update is applicable) and then to “Provisioning”. After a minute or two, you should see the final status of “Connected”.
Last step is to go to the Configuration tab of the AP in the controller website and assign it an alias name that will make it easier to track.


reference:

http://helpdesk.maytechgroup.com/support/articles/3000008280-how-to-move-a-ubiquiti-unifi-access-point-to-a-new