You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you today?

USER: I am trying to change my trip dates because my friend's are unable to come for the tour due to some important work, so we have postponed the trip. Can you help me?

ASSISTANT: Sure, I will help you on that.

USER: Thank you for taking my request.

ASSISTANT: Will you mention the name for checking the reservation?

USER: Sure, my name is Dennis Brown.

ASSISTANT: Please give me a moment.

USER: Ok, take your time.

ASSISTANT: Thank you for waiting, your reservation is found. Will you mention your travelling dates please?

USER: My changed travelling dates are 10/01 and 10/03.

ASSISTANT: Please provide your airport codes that you want to travel.

USER: My source and destination airfield codes are EWR and LGA. I am able to spend the amount up to 200, so please check for that.

ASSISTANT: There is no flights available under your preferable details.

USER: It's ok, no problem. Thank you for the information.

ASSISTANT: Welcome, have a great day.