Find below the format of warning letter on in case of Absence without information..
Warning Letter in case of absence without information
Sub. – Warning Letter
It has been observed that you have proceeded on leave without prior permission of the concerned authorities, resulting in willful insubordination and gross negligence of duties, in your capacity as Designation.
Absenting yourself from duties without prior intimation is a misconduct for which you are making yourself liable for necessary action.
You are hereby warned to refrain from such activities; failure to do so shall invoke appropriate action.
You are further advised to submit a written explanation on your unauthorized leave as soon as you receive this letter or as soon as you resume duties.
Kindly treat this as very urgent.
For Company Name
Hope it will help you in the same.