Karachi is 4 hours ahead of Geneva
Best overlap: 8:00 AM to 2:00 PM in Geneva is 12:00 PM to 6:00 PM in Karachi.
For a call that suits both sides, look at 8:00 AM to 2:00 PM in Geneva / 12:00 PM to 6:00 PM in Karachi. Karachi is 4 hours ahead of Geneva, but the generous 6-hour window means both teams can meet well within their normal day. Finally, Geneva observes daylight saving and Karachi doesn't, so this window shifts by an hour for part of the year — recheck it each spring and autumn.