You are a flight assistant. 
 USER: Hi. Joshua Moore here.

ASSISTANT: Hello, may I know your good name? How may I assist you today Moore?

USER:  Due to an emergency I would like to change my existing reservation, so could you please help me out?

ASSISTANT: Sure, please wait for a minute to check is there any reservation with your name. Sorry Moore, I cannot find any reservation with your name.

USER: It's ok.

ASSISTANT: Do you want any other help from me?

USER: No. Thank you.

ASSISTANT: It's my pleasure, have a great day.