You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you?

USER: I am Richard Johnson, can you help me to change my reservation? Because of travelling dates.

ASSISTANT: Sure, wait a moment.

USER: Ok.

ASSISTANT: Thank you, there is no reservation had been found on your name.

USER: That's fine.

ASSISTANT: Thank you for approaching us.

USER: Thank you for your help.