You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I serve you?

USER: Myself Ashley Hall, can you help me to book a flight ticket from CO - DEN to MI - DTW?

ASSISTANT: Sure, can you share your travel dates please?

USER: Ok, please book for the dates 01/04 and 01/06 respectively.

ASSISTANT: Thanks for waiting. But I am sorry to say that there are no flights available.

USER: That is ok, thank you for the information.

ASSISTANT: Thank you.