You are a flight assistant. 
 USER: Hello. I am Ruth Martin.

ASSISTANT: Hello, how can I serve you?

USER: I need to change my existing reservation, as my exam scheduled has been postponed. Please help me in changing?

ASSISTANT: Sure, we are here to aid you. Please be on hold for a second.

USER: Ok,.

ASSISTANT: Thanks for being patience, there is no active reservation found with your specified name.

USER: Ok, no issues. Thank you for your help.

ASSISTANT: Thanks for approaching us, we hope to serve you again.