How do I Handle an Unauthorised Absence?

I am an HR Manager and have received an email from an employee who has told me that he will be leaving the country for a few days to attend a family wedding. He did not seek my prior agreement to this request and since the email I have not heard from him, several days have passed. As far as I am concerned, this is unauthorised absence.  How do I handle it?

You should act quickly, unauthorised absences can be costly to any business and it is important to try and resolve such an issue as soon as it emerges. 

The first step will be to write to the employee, notifying them that the absence is unauthorised.  It is important to avoid sending a hasty response, without carefully