Nancy,
Company letter designations were based on the seniority of company captains. So, when all the twelve-month companies reorganized under the Conscript Act of April 16, 1862, new officers were elected and companies received new letter designations.
That's why 1st Company "K" became 2nd Company "E". It can be a little hard to follow when you're looking up service files for soldiers who belonged to this regiment. Officers and men came from Bellbuckle in Bedford County, Tenn.
I'm glad somebody knows how to cook!