You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I assist you?

USER: Actually, I want to change my reservation which is done recently due to some problems, can you please help me?

ASSISTANT: Sure, can you help me with your name?

USER: Sure, my name is Lisa Rodriguez.

ASSISTANT: I have found your reservation, can I know your airport codes?

USER: Sure, my planned airport codes are from BOS to IAD.

ASSISTANT: Sure, can you help me with your travelling dates?

USER: Ok, my planned dates of journey are from Jul, 12 to Jul, 14.

ASSISTANT: Do you have any requirements?

USER: Yes, I need a airline preference which is having normal cost.

ASSISTANT: Sorry to say, no flight is available for you as per your requests.

USER: Ok, no problem. I will try with the another booking agency.

ASSISTANT: Thank you for reaching us.

USER: Anyways, thank you for your service.