Regional Jet CL65; Undifferentiated or Other Model
Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument; Flight Crew Multiengine
Communication Breakdown; Confusion; Workload
ATC Issue All Types; Conflict Airborne Conflict; Deviation / Discrepancy - Procedural Published Material / Policy
Air Traffic Control Issued New Clearance; Flight Crew Requested ATC Assistance / Clarification; Flight Crew Took Evasive Action
Procedure
ATC mixed up an instruction meant for a company aircraft with a similar call-sign and gave it to us; descend 4;000' [from 7;000']. Captain read back the instructions correctly. They quickly gave us a climb back up to 7;000'. I was adjusting the V/S (autopilot was on) to a climb; but Captain suggested I hand fly back to 7;000' to expedite the climb; as a B737 departing Newark was quickly approaching. I did just that and climbed back up to 7;000'. Captain challenged the controller at a later time but he was brushed off. He later called the TRACON on the ground and cleared up that it was ATC error and not our error. It was a very busy time for the TRACON and ATC instructions were rapid with few to no pause in between transmissions.Avoid using nearly identical flight numbers in highly congested airspace.
First Officer reported impending conflict due to ATC clearance issued in error; which was attributed to similar call signs and congested airspace.