You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: Gregory Parker here.

ASSISTANT: How may I assist you?

USER: I would like to change my location codes in previous booking, can you please help me?

ASSISTANT: Sure, I will help you.

USER: Thank you.

ASSISTANT: Sorry for the trouble, there is no reservation found with your name in our database.

USER: Oh! No issues with it, thank you for checking.

ASSISTANT: You are welcome. Thank you for consulting us.

USER: Most welcome.