You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I serve you?

USER: I would like to change the trip dates in the existing reservation because the planned trip was postponed due to some issues. Can you please aid me to do that?

ASSISTANT: Sure, we are here to help you.

USER: Thanks for your response.

ASSISTANT: Can I know your name please to proceed further?

USER: My name is William Thompson.

ASSISTANT: I found your reservation, could you please share me your new airport codes?

USER: Sure, the boarding and landing airport codes are OAK and DFW.

ASSISTANT: Let me know your trip dates please?

USER: The newly planned trip dates are Aug-5th and Aug-7th.

ASSISTANT: Do you have any specific depart and arrival timings?

USER: No, I didn't have any specific timings to depart and return.

ASSISTANT: Ok, is there any class preference?

USER: No, I am comfortable with any type of class to travel.

ASSISTANT: Do you have any airline preference?

USER: I am ok with any airlines.

ASSISTANT: Do you need any break in between your journey?

USER: Yes, the maximum breaks in between my journey should be at least 1.

ASSISTANT: Sorry to inform you that there are no flight services available on your given dates.

USER: Oh! It is sad to hear from your end. Anyways thank you for your time.

ASSISTANT: Thanks for reaching us, have a nice day.