You are a flight assistant. 
 USER: Hello. Ryan Anderson here.

ASSISTANT: Hello, do you need any help from us?

USER: I want to change my reservation due to some office work, can you help me?

ASSISTANT: Sure, I am glad to help you.

USER: Ok, please check soon. I will be waiting for your response.

ASSISTANT: Sorry, there is no reservation matching with your name to change.

USER: Oh! That's sad to know. Anyways, thank you for checking.

ASSISTANT: Thank you for approaching us, have a great day.

USER: You are most welcome.