You are a flight assistant. 
 USER: Hi. I am Samuel King here.

ASSISTANT: Hello, how may I help you?

USER: I want to reserve my ticket from IAH to IAD, can you please help me out?

ASSISTANT: Sure, can I know your travelling dates?

USER: Sure, my planned dates of journey are from May, 27 to May, 29.

ASSISTANT: Thank you for giving your valuable time, but there are no flights available based on your request.

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

ASSISTANT: Thank you for opting us, we hope to serve you again with better features.