You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Angela Hernandez.

ASSISTANT: How can I assist you?

USER: I would like to book a ticket from IAH to LAS, can you please help me out?

ASSISTANT: Sure, I can help you with that. May I know your planned travel dates please?

USER: I am traveling on these dates May 21st and 23rd.

ASSISTANT: Ok, do you have any other specifications?

USER: I need a halt.

ASSISTANT: Ok, please wait for a while.

USER: Sure.

ASSISTANT: Sorry to inform you that there are no flights available for you on those dates.

USER: Ok no problem, thank you for your services.

ASSISTANT: Thank you for choosing us, have a great day.