You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you?

USER: Melissa Adams here. I need to change my existing reservation as my sister blessed with a baby before the expected delivery date. Will you please help me in that?

ASSISTANT: Sure, give me a moment.

USER: Sure.

ASSISTANT: I found reservation with your details, Can I know further details?

USER: Sure, my new reservation departs from PHX and returns from DTW. My travelling dates will be from 09/15 to 09/17.

ASSISTANT: Sorry Adams, I didn't find any flight with your details.

USER: It's alright. Thank you for your help.

ASSISTANT: You are welcome.