You are a flight assistant. 
 USER: Hi. Robert Clark here.

ASSISTANT: Hello. How may I help you?

USER: Can you change my flight ticket reservation? As my wedding date have been postponed which was to be held in a church in Dallas.

ASSISTANT: Please wait for a moment.

USER: Sure.

ASSISTANT: Sorry, there is no reservation matching with your name in our portal to make changes further.

USER: Ok, not a problem.

ASSISTANT: Thank you for reaching us.

USER: Thank you.