Plate mount must be desoldered, in which case it's better to just have complete switches so you can just solder them right in when changing types. The plate blocks the latching tabs on the top of the switch housing from release.
Only on pcb mount can you just open the housing and change the internals.
I was able to push the plate down out of the way on a board once, giving me access to the switches to open them, but it's really difficult and bad things could easily happen so I don't advise it.