Hello.
user
Hello. How can I assist you today?
assistant
Actually my friend decided to change the trip dates, because he was unable to travel on the dates he planned,  so can you help me to change his existing reservation?
user
Sure, I can help you with that. May I know your name to check the previous reservation?
assistant
My friend's name is John Green.
user
John, I see that there is no reservation found under your name.
assistant
It's ok, thank you for the information.
user
You are welcome. Thank you for contacting us.
assistant