I made a mistake on the date to go to the store. Please let me contact you again when the date is decided. What kinds of benefits am I going to have if I make an appointment?
Sorry, I informed you of the wrong day of my visit. I will let you know when I visit your shop again later. Will you let me know what is good about making a reservation?
I made a mistake with the date I will be visiting. I will contact you again when the correct date has been confirmed. What are the advantages of making a reservation?