You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you?

USER: I am Samantha Harris. Actually, I want to change an existing reservation, due to some problems. Can you help me out?

ASSISTANT: Sure Harris, Wait a moment.

USER: Ok.

ASSISTANT: There is no flight found for you.

USER: It's ok. Thank you for your help.

ASSISTANT: Welcome, thank you for choosing us.