Why are you interested in leaving your current position?

"My current role is a good position, however, I would like to advance my career into a specialist role. I intentionally took my current role to gain experience and I have volunteered for every extra opportunity possible. I have reached the peak of what this position can be and would like a new challenge in my specialty area. My employer has been trying to expand into this area, however consistent budget cuts have eliminated the advancement each time. My boss is aware of my desire for advancement and would understand if I moved to another opportunity."

"I enjoy my current position and would not be interviewing unless a position like this came along. My boss is aware I am interviewing and is supportive if the opportunity works out. This is the type of position I have wanted my entire career."