ISGAK HARDIEN
If he tells me: "Find out if Mr Williams (even though I might not know a Mr Williams, I'm just using the name for the example), Mr Williams who lives at 20 Klapperbos Street, this is his telephone number."  Perhaps I would phone first and ask to speak to Mr Williams and if they say no, he's coming home this evening, then I'll ask what time and then they'll say 7 o'clock for example, then I'll go at 7 o'clock and determine if the information is correct.