You can if your skills are sufficient. You'd swap the existing ceiling rose for the pendant fitting. You need to make sure there additional support for the pendant if it's heavier than a rose and lightshade and that you wire it in correctly. You might find you've got older wiring so the insulation in the existing wires to the fitting is red and black so you need to match that up correctly in a more modern light fitting. If you have any doubts about doing it, get an electrician to fit it.
It's pretty easy if you have a modern electrical system. You should turn off the main fuse for your lights or all electrics though, to be safe. The hardest bit is the fiddly working above your head part, screwing the bracket on etc. Matching up the wires is easy.
I've swapped ceiling roses over without a clue! I just switched off the electric and swapped over the wires. With a pendant though you may need to fix a new bracket which involves drilling holes, not so keen on that
Re above comment. Not sure about renting but you wouldn't need basic DIY work like this signed off for selling. You tend to just need an electrical cert if you've done much bigger work that's required a building warrant.