The Shulhan Aruch (Yoreh De’a 240:2) discusses the various details of the prohibition against calling one’s father by his name. It goes without saying that it is forbidden to call one’s father by his name, and must instead use a title such as "Abba, "Dad," or "Father." However, the Shulhan Aruch adds that under certain circumstances, it is also forbidden to use one’s father’s name in reference to somebody else with the same name. The Shulhan Aruch (as understood by the Ben Ish Hai, Parashat Shofetim, 2-3) distinguishes in this regard between common names, and uncommon names. If one’s father has a common name – such as Abraham, Yishak, Yaakob, Moshe and David – then he may not use this name in reference to another person with the same name, when the father is present. For example, if one’s father’s name is Yosef – which is a very common name – and the father is in the room, he may not call "Yosef" to get the attention of another person named Yosef there in the room. Since the father is present, it is considered disrespectful for the son to use that name, even in reference to another person.
When it comes to an uncommon name, even stricter guidelines apply. If the father has an uncommon name, then the son’s use of that name in any context gives the impression of calling his father by his name, which is inappropriate. Therefore, according to the Shulhan Aruch, it is forbidden to use the name even in reference to somebody else and even if the father is not present.
The Ben Ish Hai (Rav Yosef Haim of Baghdad, 1833-1909) writes that in his community in Baghdad, an example of an uncommon name with respect to this Halacha was Naftali. The Me’am Lo’ez (Rav Yaakov Culi, 1689-1732), in Parashat Yitro, gives the examples of Nahum, Noah and Machir. Later, in Parashat Kedoshim, the Me’am Lo’ez gives the examples of Yehezkel and Abtalyon. These names may not be used by somebody whose father has that name, even in referring to another person, and regardless of whether or not the father is present.
Summary: It is forbidden to call one’s parent by his or her name, and if the name is an uncommon one, then it is forbidden even to use it to call somebody else who shares the name. If the name is a common one, then one may use it to call somebody else with the same name when the parent is not present.