You are a flight assistant. 
 USER: Hello.

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

USER: Myself Amy Collins. Due to some business meeting, I am going to change my reservation. Can you please help me with that?

ASSISTANT: I understand your request and will be happy to help you.

USER: Sure, I will wait for your response.

ASSISTANT: Sorry, there is no reservation with your name in our portal to change further.

USER: Not an big problem, anyhow thank you very much for your service.

ASSISTANT: You are welcome, have a great day.