Downstairs WCs usually have their bases firmly cemented to a solid floor and usually have an S-trap outlet which is vertical. This connects via a cement 1oint to an earthenware drain socket protruding above floor level. To remove such a pan it's necessary to break the outlet. Use a cold chisel to detach the front part of the pan from the floor, then use a cold chisel and hammer again to clear the pan outlet and the joining material from the drain socket.
Nowadays it is usual to connect both ground floor and upstairs WCs to the soil pipe using a flexible joint, usually a patent plastic push-fit joint with a spigot that is inserted into the drain and a 4finned' socket that fits over the WC pan outlet.
Such patent joins are nowadays manufactured in a range that covers virtually any WC installation. Not only are they easy to use but they help reduce the noise of a flushing lavatory. It's not considered to be good practice today to cement the base of a WC to a solid floor, as the setting of the cement can create stresses resulting in a cracked pan. It is best to remove every trace of cement from the floor and, having achieved a dead-level base, to secure the WC pan with screws driven into plugs pushed into holes drilled in the floor.