15 days notice of resignation

Hi sir/mam,

An employee submitted a 15 days notice for resignation. The resignation letter was approved and signed by all his superior (Sr. manager, manager, supervisor) in his department and copy of resignation letter was submitted to HR department, after 2 days, the HR department declared the resignation invalid and they will not accept the resignation because they said it should be 30 days and not just 15 days.

I'm aware that in labor code it should be in minimum of 30 days. but given the fact that it was approved by all superior or boss in his department, Is there something in labor code or law that can be use in favor to the said employee?

Thanks in advance sir/mam!

What does the employee handbook or company policy say regarding resignation?

Thank you for the reply.

It says, the employee should render 30 days notice of resignation.

if it was approved by the boss.. then HR should accept it.