You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you today?

USER: Myself james Collins, I am willing to change my existing reservation. Can you please help me for this?

ASSISTANT: Sure, I am here to help you. Please wait for a minute.

USER: Sure, I will wait for your kind response.

ASSISTANT: Sorry, I could not find any reservation with your name.

USER: Not a big deal, anyway thank you very much for reserving the ticket.

ASSISTANT: Thanks for choosing us.