You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: I'm Samantha Mitchell here.

ASSISTANT: How may I assist you today?

USER: I want to change my existing reservation due to some health issues, can you please help me in this condition?

ASSISTANT: Sure, I will help you in changing your previous reservation. Please wait a moment, I will check your previous reservation status.

USER: Sure, take your own time.

ASSISTANT: There is no previous reservation available on your name Samantha Mitchell.

USER: That's fine.

ASSISTANT: Do you want to know any thing else from us?

USER: Not required.

ASSISTANT: Thank you for contacting us, have a good day Samantha Mitchell.

USER: Welcome.