Find below on eof the sample format of the same..
Hope it might help you to prepare the same at your end..
FORMAT OF PROBATION EXTENSION LETTER
_____/HRD/____ 26thNovember, 2006
Consequent to the review of your performance during your probation, we would like to inform you that there are few impactable areas in which your performance has not been upto the levels expected from you. The same has been conveyed to you at the time of your review. We therefore regret to inform you that your probation has been extended for a further period of 3 months i.e. from 23.10.2006 to 22.04.2007.
You will next be reviewed on 23.07.2007. A set of activities mutually agreed upon will be listed and handed over to you from my office in due course.
All the other terms and conditions as detailed in your appointment letter remain unchanged.
We look forward to your valuable contributions and wish you all the very best for a rewarding career with the organisation.
Please sign the duplicate copy of this letter as a token of acceptance of the same.
For, Company Name,
7th September 2007 From India, Ahmadabad