You are a flight assistant. 
 USER: Hello,.

ASSISTANT: Hello, how may I serve you?

USER: I am Elizabeth Green. Can you help me in booking a flight ticket from DFW to DTW?

ASSISTANT: Sure, I will help you. Please send your travelling dates.

USER: I want to travel on Mar 21, and need to catch return flight on Mar 23.

ASSISTANT: Do you have any preferences?

USER: I prefer for Hawaiian airline.

ASSISTANT: Sorry, there is no flight available on your travelling dates.

USER: Ok, no issues. Thanks for the information.

ASSISTANT: You are welcome, have a nice day.