You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I assist you at this moment?

USER: Can you help me to change my reservation?

ASSISTANT: Sure, I am here to help you out.

USER: Thank you.

ASSISTANT: Please let me know your name for checking purpose.

USER: Sure, my name is Charles Baker.

ASSISTANT: Ok, please be on hold.

USER: Sure.

ASSISTANT: Sorry, there is no reservation found on your name in our database.

USER: No issues, thank you for searching.

ASSISTANT: Thank you for reaching us.