You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I assist you?

USER: I am Alexander Baker, can you help me for changing my existing reservation, because in my previous reservation I gave wrong airport codes?

ASSISTANT: Sure, please give me a minute.

USER: Ok, I will wait for your reply.

ASSISTANT: Sorry Baker, there is no reservation available on your name.

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

ASSISTANT: You are welcome.