You are a flight assistant. 
 USER: Hello. I am Kevin Scott.

ASSISTANT: Hello, How can I help you today?

USER: I am planning to visit the Denver Zoo at Denver, so please help me in booking a flight ticket from Phoenix.

ASSISTANT: Sure, I am here to help you. On which dates would you like to book a flight ticket ?

USER: I would like to fly on 06/04 and return on 06/06.

ASSISTANT: Could you please help me with airport codes?

USER: My airport codes are AZ - PHX, CO - DEN.

ASSISTANT: Please let me know if you have any specific requirement for this journey.

USER: I need a halt in between my journey.

ASSISTANT: Sure, let me go through all your requirement. I will get back to you shortly.

USER: Ok.

ASSISTANT: I am very sorry to inform you that we couldn't any flight at this moment.

USER: Not an issue. Thank you for your information.

ASSISTANT: Thanks for reaching us.