Replacement AirPod Repair Issue

I followed the instructions for adding a repair airpod and it didn't work. Case is fully charged, I put the repair airpod in the case with the other one (original one) and I hold the button on the back of the case expecting it to turn from flashing amber to flashing white but it never does. Then when I try the old airpods together, the pairing works fine. It seems the case can't forget the old airpod. please help