You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I serve you at this moment?

USER: I need to change my reservation due to urgent meeting, can you help me?

ASSISTANT: Sure, may I know your good name please?

USER: I am Samantha Martinez.

ASSISTANT: Ok, please wait for few minutes.

USER: Sure.

ASSISTANT: There is no existing reservation found on your name in our data base.

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

ASSISTANT: Thank you for reaching us.