I have the Italeri CCKW Gun Truck. The cab is shared with their non-gun truck versions....as such the "plug" in the roof needs to be removed. I see that that is thinned but I am requesting help on the proper procedure for removing this piece of the cab. If you can please let me know how you would make this happen I would appreciate it. These are the steps I have so far.

1. Proceed slowly and carefully
2.
3.

Thank you

If I were to do this I would scribe around the plug from the inside using the back edge of the blade on the hobby knife or scalpel. An alternative tool is sharp pin or awl.
The ring (part 126B) that will be inserted into the hole afterwards will cover up small damages from the outside and some paint or glue will probably fill the joint on the inside of the cab roof.
The trick is to scribe short distances before turning the cab roof. Trying for a half or even a quarter circle in one slash will fail ...

/ Robin

You can get knives with swivelling blades for cutting curves, but you can't apply much pressure as the blades are small and break easily. Like the one at this link: https://www.pullingers.com/c/163/jakar-swivel-knife . There are several brands, all pretty much clones of the original X-Acto version.

Another alternative would be to drill a series of holes all around the outline, close to the edge. Cut through the remaining plastic between the holes and finish off by paring with a blade and/or filing out to the outline.