You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, How can I best serve you today?

USER: Can you please help me to book a flight from PHL to IAH?

ASSISTANT: Sure, can you please mention your depart and arrival dates of your journey?

USER: I want to depart on Apr 26 and need to return on Apr 28.

ASSISTANT: Do you like to go with a connecting or direct flight?

USER: I need a direct flight.

ASSISTANT: May I know if you prefer to have any other comforts in your journey?

USER: I do not have any other specifications.

ASSISTANT: Can I know your good name to proceed further?

USER: I am Brian Turner.

ASSISTANT: Sorry, no flights are available in this route as per your requested dates.

USER: Ok, no problem. Thank you for checking.

ASSISTANT: Thank you for choosing us.