The connectors at the ends of the cables are attached very firmly to the sockets on the logic board. Pulling directly on the cable will either separate the cable from its connector or the socket from the logic board.

Lift the upper case enough to disconnect the blue and white power cable from the logic board.

Using your fingernails or a dental pick, carefully pry the connector from its socket.

Make sure you are pulling only on the connector and not on the socket.