Fully close the flash unit for a better grip on the shell.

Secure the camera with one hand, and firmly grip the flash unit shell with the other.

Lift the right edge of the shell (the side closest to the charging port) to release the clips securing it.

You should feel and hear "clicks" as the clips release.

Pull the shell up and away from the camera to remove it.

During reassembly, put the shell in place and push down firmly to engage the clips.