To, Date: dd mm yyyy
Sub: Extension of Probation period.
Dear Mr/Ms xxxxxx,
With reference to the letter of your appointment dated dd mmmm yyyy, we hereby inform you that your probation period has been extended by 3 months due to your unsatisfactory performance.
During the extended period, you are required to put in your best efforts and exhibit significant improvement in your performance, failing which your employment is liable to be terminated at the end of the extended probation period.
For xxxx xxxxxx