Answer:
I'm just going to give you some examples instead of writing it.
Explanation:
The address, date, and time where the incident took place.
The manager's full name and proper email address.
Your full name, address, and contact information.
The names or descriptions of any employees involved.
An attached or enclosed receipt or order number, if possible.
Information about your history as a customer in this restaurant (how long and how often you eat there).
A compliment, if possible (to help the manager hear the criticism that follows).
Specific details (for example, don't just say the place was not clean—describe the mess and say exactly what was dirty).
Tell the manager exactly what change or outcome you'd like to see.
