You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Robert Smith.

ASSISTANT: How can I assist you at this moment?

USER: I want to change my travel dates in my previous reservation so can you please help me with that?

ASSISTANT: Sure, I will help you with this. Please give me a moment to check your reservation status.

USER: Ok, thank you for your response.

ASSISTANT: Robert Smith, there is no active reservation found under your name in our database.

USER: Oh! It's ok no problem. Thank you for your information.

ASSISTANT: Thank you for contacting us.