Commercial Fixed Wing
Flight Crew Air Transport Pilot (ATP)
Communication Breakdown; Confusion
ATC Issue All Types; Ground Event / Encounter Other / Unknown
Air Traffic Control Issued New Clearance; Flight Crew Requested ATC Assistance / Clarification
Human Factors
Similar sounding call signs. The PIT tower was calling our flight by a previous call sign (XXX8) we were (XXX6) I attempted to correct tower by responding with our proper call sign assuming it was a simple slip of the tongue. We were cleared for takeoff with that call sign. I then asked my captain if I had the wrong call sign. We confirmed the call sign and queried the tower who responded by canceling our takeoff clearance and asking our destination; [The Captain] responded with [his name and our destination and] Tower then issued a departure heading of 350 and re cleared us for Takeoff. It was a static takeoff. The aircraft did not move between the time were in position and the takeoff clearance was cancelled and we were re cleared for takeoff.
When there was confusion between ATC and the flight crew about their flight number the takeoff clearance was canceled and agreement reached between them.  A new takeoff clearance was then issued.