Use the pointed end of a spudger to pry up and disconnect the black antenna's coaxial connector.

Pry under the rounded edge of the coaxial connector, not the straight edge. If you pry under the straight edge, you may rip the socket off the daughterboard.

Use the spudger to push the antenna up and away from the phone until the cable is freed from the clip securing it to the daughterboard.

During reassembly, make sure the cable's metal band connects to the grounding clip in the daughterboard.

To re-attach coaxial connectors like this one, hold the connectors in place and gently press them straight down with your finger or the pointed end of a spudger.