You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, How can I serve you?

USER: I want a flight on 05/28 to attend my friend's birthday.

ASSISTANT: Sure, Please help me with your return date.

USER: So, I need to go there to meet all my friends and return on 05/30.

ASSISTANT: May I know the journey codes?

USER: Denver,DEN is my origin place, and destination is Boston, BOS.

ASSISTANT: Can I get your name?

USER: Sure, I am Kathleen Moore.

ASSISTANT: Please wait a second.

USER: Sure.

ASSISTANT: Sorry, No flights found with your chosen dates.

USER: Ok, I will check with other alternative. Thanks for your response.

ASSISTANT: Thank you.