You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I assist you?

USER: I am Donald Phillips, in previous reservation I gave wrong airport codes, so can you help me for changing an existing reservation?

ASSISTANT: Sure, please wait a moment I will check your reservation details and proceed further.

USER: Ok, I will wait for your response.

ASSISTANT: Sorry to say, I did not find any reservation on your name.

USER: Oh! no problem, thank you for your quick response.

ASSISTANT: Thank you for reaching us, have a nice day.