Sample Letter of Extension of Probation Period
Please check the below letter it may be helpful for you .You can do the modifications according to your requirement.
Sub: Extension of Probation period
Further to your letter of your appointment dated 12th January 09 this is to inform you that your probation period has been extended by 1 (One) month due to unsatisfactory performance. You are advised to show significant improvement in your performance during this extended period, failing which your employment is liable to be terminated, which may please be noted.