Final answer:
Six-year enlistees in the military are eligible to apply for retraining on the first duty day of the month after completing a specific number of months in their current enlistment. The exact number of months required is not provided here as the question lacks sufficient detail, and a reference to official military regulations is needed.
Step-by-step explanation:
The question pertains to the eligibility criteria for retraining for six-year enlistees in the United States military service. According to military regulation, six-year enlistees may apply for retraining on the first duty day of the month after completing a specific number of months of their current enlistment. Unfortunately, without the exact reference to the military regulation or policy document, it is not possible to provide the exact number of months required before being eligible for retraining. However, military personnel are often expected to have a certain portion of their enlistment completed and to meet other service-specific requirements before they can retrain into a different specialty.