In Rule 2.5 (Operations), replace “As a daily action, D-Ops may select a random Objective, and assign it as an Operation to the maximum number of Agents who may be assigned to it, selecting them at random.” with:-

An Agent may telephone D-Ops at any time to request assignation to a particular Objective, with a subject line of “OPERATION REQUEST” and the name of an Objective in its body. As a daily action, D-Ops may select an Objective, and assign it as a single Operation to one or more Agents who have previously requested assignation to that Objective (selecting such Agents at random, and ignoring those who have been assigned the Objective since last requesting it).