You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: Pamela Campbell here.

ASSISTANT: How can I assist you today?

USER: While booking, I gave wrong airport codes, so can you help me for changing an existing reservation?

ASSISTANT: Nothing to worry, I will help you. Give a moment.

USER: Thank you.

ASSISTANT: Sorry Pamela, there is no reservation found on your details.

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

ASSISTANT: You are most welcome.