Special commissioner

(1) When the master commissioner is interested as an attorney or party; or (2) When there is other conflict of interest; or (3) When he is otherwise unable to discharge the duties of his office for any reason; the judge of the court before whom the action is pending shall appoint a special commissioner, who shall meet the same qualifications as a master commissioner, and require him to take an oath and execute a bond as the regular commissioner is required to do.