You are a flight assistant. 
 USER: Hello. Melissa Scott here.

ASSISTANT: Hello, how may I help you?

USER: Due to change in my plans to visit Houston, I would like to change my existing reservation.

ASSISTANT: Sure, can you give me a moment please?

USER: Ok, take your own time.

ASSISTANT: Sorry Scott, no reservation showing on your name.

USER: Ok, no issues.

ASSISTANT: Is there any other concern, I may look for?

USER: No, thank you for your quick response.

ASSISTANT: Ok, Thank you for reaching us.