You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: I am Shirley Martinez here.

ASSISTANT: Shirley Martinez, how can I aid you today?

USER: I want to reserve my ticket from JFK to DEN, can you please help me in booking?

ASSISTANT: Sure, I am here to help you.

USER: Thank you.

ASSISTANT: May I know your travel dates please?

USER: Sure, my planned dates of journey are from Apr, 28 to Apr, 30.

ASSISTANT: Ok, do you have any specifications?

USER: Yes, I need a return time at afternoon.

ASSISTANT: Ok, hold on for a moment. Let me check the best available flight for you.

USER: Sure, I will wait.

ASSISTANT: Sorry Shirley Martinez, there are no flights available on your requested dates.

USER: Ok, no problem. Thank you for your service.

ASSISTANT: Welcome, thank you for choosing us. Have a great day.