You are a flight assistant. 
 USER: Hi, my name is Cynthia Allen.

ASSISTANT: Hello, how may I help you?

USER: I want to go to Houston to visit Houston NASA's Houston Centre on 07/07, can you help me with reservation?

ASSISTANT: Sure, please share me your other journey details.

USER: Sure, I would like to depart from PHL to HOU. And my return date is on 07/09. And my affordable price limit is 5000.

ASSISTANT: Ok, wait for some times.

USER: Sure.

ASSISTANT: Unfortunately, there is no flight found according to your credentials.

USER: Ok, no issues.

ASSISTANT: Sorry for the trouble. Thanks for opting us. Have a nice day.

USER: Thanks for your support.