I work with a gentleman 50 years old. I have known him for 20 years, he has been in the same skill set for all or most of those years. He has recently been asked to perform other duties such as repacking corner blocks. This seems to be very challenging for him! He's very knowledgeable about his assigned duties, but when asked to perform something different other than what he normally does, he becomes frustrated, and becomes very combative. Do you have any suggestions as how to approach the issue?