You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you?

USER: I want to change my existing reservation on the name of Kathleen Perez.

ASSISTANT: Sure, please wait a while.

USER: Ok.

ASSISTANT: Thanks for being patient. We didn't found any reservation by this name.

USER: Not an issue. Thanks for your service.

ASSISTANT: Thank you for opting us.