You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you today?

USER: I had done my booking last week to meet my grand mother. But accidentally my grand mother came to my home.So, I would like to change my flight ticket. Can you help me to change reservation?

ASSISTANT: Sure, I can help you with that. May I know your name to proceed further?

USER: I am Charles Mitchell.

ASSISTANT: Please allow me a moment to check the details for you.

USER: Sure.

ASSISTANT: Thank you for waiting. Charles, there is no reservation found under your name.

USER: It's ok, no issues. Thanks for everything.

ASSISTANT: You are welcome. Thank you for contacting us.