If an authorising officer in relation to a controlled operation becomes satisfied that the principal law enforcement officer for the controlled operation ceases for any reason to have responsibility for the controlled operation:
(a) the authorising officer may, by instrument in writing, nominate another person as the principal law enforcement officer for the controlled operation; and
(b) with effect from the execution of the instrument or such later time as is specified in the instrument, that other person becomes the principal law enforcement officer for the controlled operation.