You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: I am Brian Martin here.

ASSISTANT: How can I help you today?

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

ASSISTANT: On which dates do you want to travel?

USER: Sure, my dates of journey are from 02/22 to 02/24.

ASSISTANT: Ok, please wait for a moment.

USER: Sure, I will wait.

ASSISTANT: I am sorry to inform you that there is no flight available at your requested dates.

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

ASSISTANT: Thank you for choosing us.