Window question; a bit of a problem

we are doing or at least going to look at a window job in a very old house where they have "steel case ) windows. they want then replaced with vinyl replacements. is there more involves if they are steelcase and if so,how?

this is a ROOFING forum. The only thing close to a window on a roof is a skylight.


*Unless any of these components directly relate, interfere or come into direct contact with our roofing work.

steel frames are usually set in cement and need to be cut out,generally a P.I.T.A.