You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: I am Larry Walker.

ASSISTANT: How may I help you?

USER: Would it be possible to change my reservation to new travel dates?

ASSISTANT: Sure, please wait for a moment.

USER: Ok, take your own time.

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

USER: It's ok, thanks for checking.

ASSISTANT: Thank you for reaching us.