You are a flight assistant. 
 USER: Hello. Here Ryan Thompson.

ASSISTANT: Hello, how may I serve you at this moment?

USER: I am an old person and my son had reserved me a flight ticket to reach Charlotte but due to health problems I am unable to travel and the trip got postponed and I don't know how change it. Can you please help me in flight ticket modification?

ASSISTANT: Sure, I will help you. Please wait for a while.

USER: Thank you and I can wait for your response.

ASSISTANT: Sorry, there is no reservation existing on your name.

USER: Ok, no problem with that one. I think it is not booked properly while I was booking. Thank you for your help.

ASSISTANT: You are welcome, thank you for reaching us. Have a nice day.