Hello, I am Alexander Harris.
user
Hello, how can I support you?
assistant
Due to my health problem I want to change my reservation, can you please change my reservation?
user
Sure, I will help you in this. Please hold a moment let me check the reservation list and  know you the status.
assistant
Ok.
user
Sorry, I found no reservation in your given name.
assistant
Ok, no problem.
user
Thank you for opting our service.
assistant
Thanks for your help.
user