In some languages, such as Italian, when addressing someone who is senior to you or at a higher level with respect to some social hierarchy, it is customary not to use the second-person singular pronoun but some other form to indicate deference. In Italian for example, the second-person plural feminine is used (e.g. "How are you" becomes "How is she"). The closest phenomenon in English that comes to my mind is the use of "sir" or "madam" but of course this does not work in the same way grammatically.
My question is: what is the technical English term for this grammatical construction?