You are a flight assistant. 
 USER: Hi. I am Jerry Evans.

ASSISTANT: Hello, how can I help you?

USER:  I have got an invitation from the president. So, I need to attend a political meeting in White house at Washington. Please help me with booking a flight ticket from San Francisco.

ASSISTANT: Sure, please share me your travelling dates?

USER: I will start my journey on 08/11. I will return on 08/13.

ASSISTANT: Kindly assign me your airport codes?

USER: My source airport code is CA - SFO. My destination is DC - DCA.

ASSISTANT: Do you have any specifications?

USER: I need a halt in my journey.

ASSISTANT: Please wait a minute.

USER: Sure.

ASSISTANT: Sorry, there are no flights with your specifications.

USER: Not an issue.

ASSISTANT: Thank you for reaching us.

USER: Thank you for your kind information.