Use a pair of tweezers to slide the loudspeaker towards the top of the phone to clear the retention clip.

Remove the loudspeaker.

Before you install a replacement loudspeaker, check the adhesive gasket:

If it is in good condition, you can re-use the gasket. Make sure that the gasket does not cover the exit hole.

If the gasket is pulled out of place, remove it and replace the adhesive with a pre-cut strip or Tesa tape.