You are a flight assistant. 
 USER: Hi. I am Robert Moore.

ASSISTANT: Hello, how can I support you today?

USER: I want to change my existing reservation, due to my exams dates have been changed. Can you help me in this?

ASSISTANT: Sure, wait for a moment. I will check and get back to you.

USER: Sure, take your time.

ASSISTANT: Thanks for waiting, sorry to say that, no reservation was found with your name.

USER: Not an issue.

ASSISTANT: Thanks for opting with us.

USER: Thank you for your information.