You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: I am Scott Davis.

ASSISTANT: How may I render you today?

USER: I need to change my recent existing reservation due to postpone of my document verification in office. Can you help me?

ASSISTANT: Sure. Please wait, I will revert to you.

USER: Ok.

ASSISTANT: Thanks for your time. But, there is no reservation done previously to proceed.

USER: it's Ok, thanks for your response.

ASSISTANT: Thanks for your time.