O de gozaimasune kashikomarimashita shoushou omachi kudasai
Mr./Ms. O right? Just a moment, please.
O desuga,X san wa irasshaimasuka
This is O speaking, may I speak to Mr./Ms.X?
May I ask who's calling?
XX no O sama de irasshaimasune
You're Mr./Ms. O of XX, aren't you?