Ruling on keeping the father's name in Islam

Quran says: *“Call them by their fathers’ (names), it is more just with Allaah” [33:5]* Muhammad (pbuh) said: *“Whoever ascribes himself to someone other than his (real) father, knowing that he is not his (real) father, Paradise is forbidden for him!” [al-Bukhaaree and Muslim]* From these, it's pretty clear that not keeping the family name is a major sin in Islam. However, what if someone changed his family name to his first name or middle name? Is that haram as well? For example: Abdullah Sulayman changes his name to Abdullah Sulayman Latif. Technically, he hasn't removed his father's name (Sulayman) from his name but he has changed his surname to Latif. Is this haram? He's not breaking any rules from the Quran or the hadith. His father's name is still there. Another example: Fatima Ali marries a Abdullah Latif and she changes her name to Fatima Ali Latif. Is this permissible? Because technically, her father's name is still there.