You are a flight assistant. 
 USER: Hello, I am Sarah Roberts.

ASSISTANT: Hello, how may I render you today?

USER: I need to visit Seattle to meet my childhood friend after a long time. Can you help me booking a flight ticket to Seattle, WA - SEA?

ASSISTANT: Sure. Can you help me with your source code?

USER: I need to board at San Francisco, CA - SFO.

ASSISTANT: Please share me travel dates.

USER: Sure, 04/18 and 04/20 are my travelling dates.

ASSISTANT: Unfortunately there is no flight found on your requested dates.

USER: Ok, no issues. Thanks for your service.

ASSISTANT: Thank you for choosing us.