On ours, if its still the same, the bottom retainer (runs the width of the plate) can be easily prised/pulled forward and pops off - work from one end, they are just a series of plastic poppers - but it does feel like you are going to snap something. The plate can then be slid out the bottom. Takes about 5 seconds! A plate nickers dream...
Reverse is just as easy. Slide new (thin metal) plate in from the bottom, yellow plate at back, white at front, and make sure it is fed behind the little lugs and correct orientation. Then pop the bottom retainer back on, one popper at a time, ensuring each is firmly secure and any wording is the correct way around. Takes about 10 seconds.