It is the duty of a judge of a court of this State to continue a case in the court on or without motion when a party to it or his leading attorney is absent from court when the case is reached by reason of his attendance on active duty as a member of the National Guard or reserves. The case may proceed if the party, in the absence of his leading attorney, or the leading attorney, in the absence of the party, announces ready for trial on the call of the case. If counsel is absent, it shall be necessary for his client to make oath that he cannot safely go to trial without the absent attorney and, if a party is absent, his counsel shall state in his place that he cannot safely go to trial without his client."