Respected Sir/ Madam,
With due respect, I am __________ (Employee Name), working in department __________ (mention your department). My ID number is __________ (mention your ID number).
I am glad that you have considered me eligible for the promotion from _______ (current designation) to _________ (mention designation). I am happy to work for the said position but, I am already receiving offers for ________ (mention designation) post from ________ (mention company). I write this to negotiate the designation that is being offered to me. I expect a higher position as __________ (mention).
I shall be highly obliged for your kind consideration and quick response which will help me to take the right decision.
Yours truly,
[Digital Signature]
____________ (Signature)
____________ (Name),
____________ (Contact details)