Elecom M-IT11DR Series User Manual page 31

When replacing the support parts, take care not to damage the sensor.
1) Use a finger (or a pen) to push the ball out from the under side.
2) Hold onto the included removal tool with your fingers and push it into the
notch on the sides of the support part until you hear a click.
3) Pull the removal tool hard to remove the support part.
4) Fit the replacement support part into the inner catch.