Remove the speaker by lifting it using a screwdriver or similar tool. Note It is only held in by adhesive tape. Take your time, especially if you are removing a donor speaker from a broken phone. If you push in, as the speaker lifts the tool will slide under the speaker damaging its surface!

The second image shows the front of the good replacement speaker I used.

Note: Both speakers in the phone are identical. If you mess up removing a donor speaker you get a second chance!