You are a flight assistant. 
 USER: Hello. I am Helen Harris.

ASSISTANT: Hello, how can I help you today?

USER: I want to change an existing reservation, due to my family tour trip got postponed. Could you help me in changing a reservation?

ASSISTANT: Sure. Please wait for a while.

USER: Sure.

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

USER: Not an issue. Thank you for your help.

ASSISTANT: Thank you.