If you’re not available, due to illness or vacation, for example, how will your patients be cared for?
This is a straightforward question and the answer is always part of the by-laws of any institution. If you're not new to the area, you should identify others on staff with whom you expect to have a reciprocal on-call relationship; if you're new to the area, you should state you intend to be full-time responsible until you can establish such reciprocal relationships. An extra overture would be to say you plan to serve on many committees in order to meet others in your specialty.
"I plan to serve on committees within your department so that I can enter into some reciprocal call agreements with other staff members, as soon as possible. However, I won't be taking much time off as I build my practice, because the low numbers will not be too taxing before it gets built up over time."
