The bottom of the daughterboard is connected to the motherboard via a press connector.

Insert a spudger between the edge of the daughterboard and the motherboard.

Pry up with the spudger to disconnect the press connector and separate the daughterboard from the frame.

Remove the daughterboard.

To re-attach press connectors like this one, carefully align and press down on one side until it clicks into place, then repeat on the other side. Do not press down on the middle. If the connector is misaligned, the pins can bend, causing permanent damage.