You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assess you?

USER: Donald Turner here. Can you please reserve a flight ticket from IAD to SFO for a business meet?

ASSISTANT: Sure, can you provide the moving dates of your journey?

USER: I am planning to leave on 06/08 and please book my return ticket on 06/10.

ASSISTANT: Please give me a minute.

USER: Sure, take your time.

ASSISTANT: No flights that are moving on the dates which you have mentioned.

USER: Oh! So sad to hear that. Anyway, thank you for the information.

ASSISTANT: You are welcome and have a nice day.