You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I help you today?

USER: I am Timothy Lopez, want to alter my reservation dates. Can you please help me?

ASSISTANT: Ok. I will help you with that. Please wait for a minute.

USER: Ok.

ASSISTANT: Sorry to say that, there is no reservation found on your name in our database.

USER: It's ok, thank you.

ASSISTANT: Thank you for approaching us.