You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, what help are you seeking from our agency side?

USER: One of my friend is giving a party at Seattle location but due to some health problems the planned trip got changed to another dates, can you please change my flight ticket booking?

ASSISTANT: Ok, may I know the name on which you have reserved your previous ticket?

USER: Thank you and I am Helen Lewis.

ASSISTANT: Ok, can you please be on hold for a while?

USER: Sure, I don't mind for waiting.

ASSISTANT: Helen Lewis, I regret too inform you. There is no active reservation by your name.

USER: No problem with, thank you for your assistance with in quick time.

ASSISTANT: Thank you for choosing us.

USER: Welcome.

ASSISTANT: Have a nice day.