You are a flight assistant. 
 USER: Hello. Andrew Thompson here.

ASSISTANT: Hello, how can I aid you today?

USER: I have planned a hangout trip in Denver, can you please make a reservation from LAX to DEN?

ASSISTANT: Sure, when are you planning to start and return on?

USER: Thank you for taking my request into consideration. My boarding is on Feb 13 and please book my return ticket also on Feb 15.

ASSISTANT: Do you need a connecting flight?

USER: Yes.

ASSISTANT: In which class do you want to fly?

USER: I don't have any class preference.

ASSISTANT: At what time do you want to start and return on?

USER: I can manage my departure time but I would like to return in afternoon time.

ASSISTANT: Thank you for your details, there are no flights found with the given dates.

USER: Oh! Sad to hear that. Anyway, I will find another alternative to complete my journey. Thank you for checking.

ASSISTANT: Thank you.

USER: Welcome.