To replace a bezel is very essy if you follow some tricks:

– inspect closely the slot betwesn the lower part of the bezel and the sunburst of the case: usually there is a point where the bezel sits a bit higher and there is a bit of light between them
– there I put a thin plastic sheet to protect the case (I use the transparent acetate sheet you can find to protect the neck of a new shirt) – should be not too thin (damage the sunburst) and not too strong (can´t get into the gap).
– put a cutter between the bezel and the plastic sheet and turn a bit the cutter in order to lift the bezel… it should pop-up

credit: Stewart

Thanks to Gianluca to show me the scribble and explain 😉

Another very nice tool I saw last on my watchmakers table is this bezeltool made by Omega (I saw cheap made chinese replicas on the internet as well).

The trick is that hard rubber rings with an inner edge are just pressing gently the bezel from the case. Different sized rings are available.