You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you today?

USER: Due to sudden health issue, I am not able to travel in a flight on those date that I want to travel. So, I would like to change my reservation. Can you please help me out with that?

ASSISTANT: Sure, will you mention your name please?

USER: Than you for accepting my request, I have reserved it on the name of Richard Lewis.

ASSISTANT: Please give me a moment.

USER: Sure.

ASSISTANT: Thanks for waiting, there is no reservation found under your name.

USER: Oh! No issues. Anyway, thank you.

ASSISTANT: Welcome, have a great day.