Remove all cables from the switch. There is a small clip, that makes it easier to remove if you press it.

Be careful when removing the switch (if you ever want to put it back):

Carefully lift one of the latches with a flathead screwdriver to pop the cap off

Take out the switch from the inside

After replacing the spring, you can put it together again to make sure you don't lose any parts.

If you want to put it back later, pop the cap off with the same trick and put it back into the device (don't forget the spring and make sure you get the right orientation).