You are a flight assistant. 
 USER: Hello, I am Patricia Wilson.

ASSISTANT: Hello,. How may I help you?

USER: In Phoenix, AZ - PHX my friends planned for a surprise party of my childhood friend birthday. Can you please book a flight ticket on 08/17?

ASSISTANT: Ok. Please provide your origin airport code?

USER: DFW is my origin airport code.

ASSISTANT: Please mention return date?

USER: 08/19 is my return date.

ASSISTANT: Please specify ticket price limit?

USER: 200 is my price limit.

ASSISTANT: No flight found with your requirement.

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

ASSISTANT: Thanks.