Hi Sonal,
Instead of re-issuing the appointment letter with revised salary, what you can do is send them an increment letter.
Find below the format for your perusal:
=====================================
Date
Dear [Name],
Sub: Increment Letter
We are happy to inform you that based on your sustained performance over the tenure of your service since [Date of Joining] and on recieving satisfactory reports from your superiors, we wish to revise your compensation as described as under.
Basic - Rs.
DA - Rs.
HRA - Rs.
Conveyance - Rs.
Medical - Rs.
(Use your own format of compensation. I mentioned the above titles based on generic break up)
Please note that all the conditions of employment however, would remain same as per the order during your tenure of service with our organization.
We wish you all the very best in your career with our organization.
Regards,
Authorized sign
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Whenever any changes are made in the employment terms, it is always better to have a written application for it.
If you are changing the services or roles of the person, similar letter should be assigned to the concerned person(s).
This kind of letter helps company keep a track of what is being communicated, who does what, who is being compensated at what rate etc.
Above all, such letters are very essential to be filed properly and preserved in case of Audit. (Companies have to do HR Auditing just like financial Auditing)
Note:
Always issue such letters in two copies.
One copy would be handed over to the employee.
On the other copy, employee's signature should be taken and should be filed with other documents.
Hope it helped. :-)