First Officer reported a loss of thrust on the right engine. The Flight Crew elected to perform an in flight shut down of the affected engine and diverted to make a precautionary landing.

Narrative

We were operating Aircraft X from ZZZ to ZZZ1. Captain was pilot flying. Departure out of ZZZ was normal. In the initial climb we had to deviate around some weather but otherwise enroute weather looked great. We had been assigned the ZZZZZ5 arrival into ZZZ1. ATC then gave us direct the ZZZZZ intersection for the ZZZZZ arrival and to maintain 300 knots which we did. As the Captain advanced the thrust levers; we experienced a yawing moment and at that point it was clear we were losing thrust on the right engine. We decelerated pretty quickly to about 220 knots due to the reduced thrust on the right engine. The Captain moved the right thrust lever forward and back a couple times and we were only getting a small response with the engine thrust stuck at a low power setting. At that point we advised ATC we were unable to maintain 300 knots due to a right engine issue and told them to standby. At that point the Captain called for the QRH. Upon looking at the procedures; neither one of us crew members could find a QRH that seemed applicable. We had received no EICAS messages; all the needles were in the green. We also checked the system synoptic pages and found nothing abnormal. By that time the right engines thrust was much lower. At that point was when we [requested priority]. We discussed continuing to ZZZ1 but because the Powered Fuel Cross Flow on the aircraft was MELed; we were a little concerned of the possibility of a fuel imbalance if the gravity cross flow would not keep up. That is when we decided to divert to ZZZ2 which at that point was about 45 miles to our Northeast. Due to partial power still on the right engine we elected to accomplish an inflight engine shut down in accordance with the single engine procedures QRH. The Captain did a great job of relaying the necessary information to the flight attendant and the passengers. We were also in contact with dispatch via ACARS. We then proceeded to set up for the RNAV XX into ZZZ2 and landed using the single engine approach and landing profile. Upon touching down we were met by emergency vehicles who inspected the aircraft after we came to a full stop. We taxied to the gate. I feel the Captain did a great job with CRM and we were able to work together very well to overcome the mechanical malfunction. The flight attendant also did an out standing job keeping the passengers calm. This was my first real emergency. These emergencies always come when you least expect it. For us it was last leg of a long day. I am very happy with the way that the Captain and I were able to work together to get everyone on the ground safely. We were able to maintain a very professional working environment and our CRM was very good. The flight attendant did a great job as well. Although there was nothing we could do to prevent this from happening my take away is to keep reviewing emergency procedures and to be very familiar with the QRH as that really makes things a lot easier when you are in situation like this.