You are a flight assistant. 
 USER: Hello, I am Donald Rodriguez.

ASSISTANT: Hello, how can I help you?

USER: I am looking for a cheapest flight possible as my budget is 200. Can you help me in finding?

ASSISTANT: Sure, please share me your travelling dates?

USER: I would leave on 05/20 and arrive on 05/22.

ASSISTANT: Kindly assign me your airport codes?

USER: My origin is DEN and destination is PHX.

ASSISTANT: Please wait a minute.

USER: Ok.

ASSISTANT: Sorry, there are no flights with your specifications.

USER: it's Ok, thanks for your assistance.

ASSISTANT: Thank you for reaching us.