Person wants to know when to be at home to receive your phone call. If in Germany, and you're in New York, their clock will be ahead of yours by 6 hours. That is, if you want to call them around 11 pm their time, you'll need to call at 5 pm. New York time. If you're one time zone to the west of NY, call at 4pm your time to get them at 11 theirs. :)