Final answer:
The Battalion Human Resources must process a DA 4187 form submitted by a Company Commander denying an automatic promotion, ensure it is in line with regulations, update personnel records, and inform the affected soldier.
Step-by-step explanation:
When a Company Commander submits a DA 4187 denying an automatic promotion for a soldier, the Battalion Human Resources (BN HR) department is responsible for processing the form and updating the soldier's personnel records accordingly. The BN HR must review the request to ensure it complies with promotion regulations and the reason for denial is substantiated and valid. Following this, they must input the denial into the relevant personnel management systems and notify the soldier of the decision, informing them of any possible recourse or actions they can take in response to the denial. This can include guiding the soldier on how to address the issues that led to the denial of the automatic promotion.