The change was prompted by Guillen’s disappearance at Fort Hood.

In the wake of the high-profile disappearance of Army Spc. Vanessa Guillen earlier this year, as well as other high-profile incidents, the Army will soon list soldiers who fail to report to duty as “missing” and will prioritize taking “immediate action” to locate them, according to an internal Army message.

“ln the coming weeks, HQDA (Headquarters, Department of the Army) will publish guidance on absent Soldiers to clarify that when one of our teammates fails to report for duty, we will consider them missing and take immediate action to find them,” top Army leaders said in a message to soldiers stressing the importance the Army places on its people.

Army leaders have acknowledged that the disappearances of Guillen and Pvt. Gregory Wedel-Morales, who disappeared from Fort Hood last year, led them to reassess the current practice of quickly listing soldiers who do not report for duty as absent without leave, or AWOL.

“How quickly can you see is it involuntary or voluntary? Are they missing?” Army Secretary Ryan McCarthy told ABC News’ “20/20” in an interview in September.

Gen. James McConville, the chief of staff of the Army, told reporters on Thursday that the upcoming changes will address “confusion” about the existing AWOL policy among commanders.

McConville said that under the change in policy the default will be to consider soldiers as missing.

“They only become AWOL after thorough investigation, thorough looking for the soldier, dealing with the family, dealing with law enforcement, we can prove that they are absent without leave,” said McConville.

“If a soldier is not present for duty, they are missing,” said McConville. “And we will continue to do all we can do, just like we would in combat, to find them and get them back.” He encouraged junior commanders to reach out to the families of soldiers in their units to establish relationships that could help determine a soldier’s state of mind if they don’t report for duty.

Though Guillen was not listed as AWOL after her April disappearance, and her unit quickly carried out a broad search for her whereabouts, her family complained that base officials did not initially make a major effort to find the missing 20-year-old soldier. Guillen’s remains were eventually found several months later, allegedly murdered by a fellow soldier who took his own life as law enforcement officials closed in.

Going AWOL is a frequent occurrence in the military; through the end of August there had been 830 AWOLs reported throughout the Army worldwide. Many service members in that status end up returning to duty and some face disciplinary action for their absence.

A service member who does not return to duty after 30 days is dropped from the rolls and listed as a deserter. The military services do not make it a priority to look for deserters.

Wedel-Morales disappeared from Fort Hood in August 2019, just weeks before he was to leave the Army. He was listed as AWOL and dropped from the rolls after the 30-day period.

His remains were uncovered in June of this year based on information provided as part of the investigation into Guillen’s disappearance. Army investigators later determined that his death was the result of foul play while he was on active duty.

That conclusion led to the restoration of his rank and military benefits for his family, that included the costs associated for his military funeral.

“They failed on every level. To look for him. To protect him. And if nothing else, just to call and say we’re sorry, we screwed up,” his mother Kimberly Wedel told 20/20 in September.