You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you at this moment?

USER: I need to change my previous reservation because my friends are changed the travel dates. Can you help me?

ASSISTANT: Sure, I will help you, may I know your name please?

USER: My name is Brenda Martinez.

ASSISTANT: Martinez, wait for a moment to check your reservation status.

USER: Ok, take your own time.

ASSISTANT: Brenda, but I did not found any reservation with your name.

USER: It's ok, thank you. I will reach you in future, if I require any help from your agency.

ASSISTANT: My pleasure, you are always welcome.