You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: My name is Edward Nelson.

ASSISTANT: How may I help you?

USER: I would like to travel from OAK to DEN, could you help me out?

ASSISTANT: Sure, please share your travel dates.

USER: My preferable dates are from 04/14 to 04/16.

ASSISTANT: Sorry, no flights available at this moment.

USER: That's ok.

ASSISTANT: Thank you for reaching us.

USER: Thank you, have a good day.