Geneva is 6 hours ahead of Washington, D.C.
Best overlap: 8:00 AM to 12:00 PM in Washington, D.C. is 2:00 PM to 6:00 PM in Geneva.
The hours that work for both Washington, D.C. and Geneva are 8:00 AM to 12:00 PM (Washington, D.C.) and 2:00 PM to 6:00 PM (Geneva). The shared window is roughly 4 hours; treat its midpoint as the default and you'll keep both teams happy.