I wanna change my toilet

Based on your description I’m guessing the plastic pipe is the flush pipe that comes from the cistern and connects to the back of the pan? If so there is no reason why you couldn’t replace it with what’s called a close coupled toilet. The only two things you may want to consider is the location of the feed, this may need altering as a close coupled toilet is typically fed from below the cistern oppose to a side entry. The second thing you may want to look at based on your description of the toilet being “old fashioned” is the waste connection, some of these older houses have cast iron waste pipes which are smaller in diameter than the 110mm (4”) we use today, some are only 3.5” and will require cutting the knuckle off of the front with a grinder or hacksaw and installing an adapter. I hope this helps!

This should be relatively easy for DIY skillsets The biggest problem you may find is the waste postion Older low level wc s may go down through a floor and more often than not is set too far forward from the rear wall If not your in luck There are many adaptors to help you The water feed will need to be altered to a lower position to fit the cistern If I were you I would isolate the water and fit a decent service valve to the feed low level then repipe from that Hope it goes well for you

Can fit either, but will probably need adjustment to pipework. Also cistern will be lower on wall. Advise you use a professional tradesman for project.

in short the answer is yes, you should be able to swap out the old style toilet for a more modern close coupled design. however you need to look at how the waste is located and how the existing wc pan is connected to it, with some older toilets sometimes this element of the alteration can prove difficult so you need to get professional advise really.