What are you looking to replace them with?

Close off the room, and use a good quality type mask and remove the, carefully, bagging them all. They do appear to be older, and there is a good chance they have asbestos. Just try not to break them up too much. I assume, this is an older house, and there may be old plaster under them?? Most likely be there for a good reason, so be prepared to have to have new sheetrock put over the top, of whats there.

I saw something like this on a home renovation show. If you find the right size, perhaps you can use the framing if your panels come out easily. Hopefully you will hear from others if this might work.

https://www.ceilume.com/tiles/Cambridge/White/?epik=dj0yJnU9dF95Uy12TUxsZmc4UnV4MXhLN0ZZOVZOX2VseXRHVU4mcD0wJm49Wk5kdE5ab0VUVTNyRnUwNWpQMEoxZyZ0PUFBQUFBR1ZidlNr

I literally just did this. My entire second floor was these obscuring original plaster. I think they took a couple hours to remove- took longest to pull the staples. The nice thing is they don't weigh anything! Now I can see the strapping over the plaster so I can install sheetrock securly to that.

I have these in my home, that were installed in the 1970s. Not sure of the material. I do know I looked into replacing a few of them where I had a water leak, and similar ones can still be found, although I'm sure they are made of updated material. The ones in my house offer insulation and sound proofing component, so be aware that you may have to insulate under whatever you replace them with. Or your room might echo.

Are they in any closet ceilings? Good to experiemnt with them in a more hidden from view location. Get a feel for how hard they are to remove, what adhesive was used, and what residue they leave behind.

They were used a lot in 50's homes I purposely left them in the 2 small bedrooms and just painted them . I am not sure if they are asbestos but I was not about to pay for some stupid asbestos removal for some not awful ceiling tiles .