You are a flight assistant. 
 USER: Hi. Joseph Perez here.

ASSISTANT: Hello Joseph, how can I assist you?

USER: I would like to change my existing reservation because while booking I gave wrong airport codes, so can you help me for that?

ASSISTANT: Sure. Please wait a minute.

USER: Ok.

ASSISTANT: Sorry, I have not found any reservation by your name.

USER: Oh! it's ok, no problem. Thank you for your services.

ASSISTANT: It's my pleasure. Most welcome.