Guitaret wroteHere's the technical answer to your question, I will state some of the process common in name in Latin Arabic (I don't have an arabic keyboard atm).
When you want to register the apartment at "Daweyir", you will be asked to submit a "kimeh ta2jiriyeh", this is a paper you need to bring from "meliyeh" from the region of the apartment is in (mine is melyit baabda).
This paper is a whole process by itself, and one of the papers you need to bring to have it, is called "Ifedit motawayet" which mean you need to have an official paper that declares what is in your property at the time of purchase.
This is usually done by "baladiyeh" or "mo5tar" (if you dont municipality there), which mean that a guy comes to your house and list all the divisions you have (how many balconies, bedrooms, parking, garden, terrace...)
If you bring that paper back that shows a different composition that what is in the official map (or "sakk a5dar"), you will be committing a "mu5elafeh" that might bite you in the behind to fix.
Usual fixes:
Try to sort it out with the baladiyeh guy coming to your house, tell them the situation and why there was a change, dunno if you want to offer something (I am too shy to to do that to be honest, I ask another person to do it...)
Or else, if the change could not be justified or sorted out, you must revert it before issuing the "Ifedit motawayet". Demolishing a wall is easier than dealing with a "mu5elafeh" (I can promise you that)
Thank you very much for the detailed explanation! Guitaret our real estat expert!