The solution to this problem, like most problems, is simple as long as you know the answer.
Ubiquiti WiFi access points such as this UAP AC Lite are designed to be affixed to ceilings.
The actual access point is attached to a base that is firstly affixed to the ceiling.
The access point is then fitted to the base and rotated so that the tang on the base (arrowed) goes over the rotational stop and locks in to the slot of the access point.
To remove the access point the tang of the base needs to be raised so the access point can be rotated and removed. This is easy when the unit is not fitted to the ceiling as you can lift it with your finger.
When it is fitted to the ceiling though you have to insert an object through the small access hole (arrowed) and lift the tang
No keys or tools are supplied with the access point for removal. Screwdrivers don't really fit into the access hole as they are too big and there is not much room available when the access point is fitted to the ceiling.
The ideal solution is a steel wire paper clip. The bigger the better as long as the wire diameter of the paper clip goes through the access point hole, This 50mm long paper clip seems the ideal size.
With a pair of needle nose pliers, straighten out the outside bend as shown.
Then bend the now straight portion back around to 90°
Now half way between the 90° bend and the end of the wire, bend the wire 45° to the left and then 5mm closer to the end of the wire put another 45° bend in this time to the right.
The bent paper clip can now be inserted into the access hole of the access point.
Now rotate the paper clip up the the left, the 45° bends in the wire lift the tang clear of the rotational stop.
The access point can now be rotated anti clockwise (looking from underneath) and removed from the base unit.
A simple solution to a tricky problem that can be made with an item found in any office or home.