Hello, I am Jennifer Baker.
user
Hello, how may I help you Mr. Baker?
assistant
I want to modify my trip dates of my  existing reservation as my plan got changed. Can you help me in this regards?
user
Sure, I am glad to help you, please wait for a while,I will check and get back to you.
assistant
Ok.
user
Sorry to inform that there is no reservation on your name.
assistant
Ok fine. Thanks for you response.
user
Thank you for approaching us.
assistant