A warning letter will let the employee know that a specific action is not acceptable and can encourage an employee to rectify his or her behavior.
If the letter is being sent as a hard copy, then it should be in the proper business format, otherwise, if the letter is being emailed, it should have an appropriate subject line and proper grammar.
This letter is an official reprimand for your failure to arrive on time for your shifts as they are scheduled. We noted that you were at least 20 minutes late on five separate occasions.
In our line of business, it is very important that all of our customer service representatives arrive on time every day. Therefore, your failure to perform this duty is unsatisfactory. Our customer service representatives must be available to operate the phones in order to provide our customers with the best service possible.
When you do not make the effort to arrive on time, we are forced to ask another employee to work overtime for you. This demonstrates that you have no regard for your co-worker's time. In addition, your employer must pay your co-worker overtime every time this behavior occurs.
Our human resources department verbally counseled you the many times that you arrived late or were absent in the past. Apparently, the verbal counseling did not have the effect on your conduct that we hoped it would have. Therefore, the purpose of this written reprimand is to remind you of why it is so important for you to arrive on time for your scheduled shifts. It is part of your job description.
If you do not begin to arrive for your scheduled shifts on time, we will be forced to take further disciplinary action, and it may include employment termination.
Your official file will contain a copy of this written reprimand.
Signature
[Supervisor's Name]