You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I serve you?

USER: I am Christopher Lewis. I would like to attend my colleague's ring ceremony, so could you please help me with booking a flight ticket on 12/28 along with a return ticket on 12/30?

ASSISTANT: Ok. May I know your airport codes?

USER: Sure, I am heading from MSP to SFO.

ASSISTANT: Do you have any preferences?

USER: I am looking for a flight within price 200. There should be a halt within my journey.

ASSISTANT: Thanks for your details. There is no flights found on your data.

USER: No issue, thank you.

ASSISTANT: Thank you.