To allow reducing number of slots for certain dates in an appointment

Currently for one appointment, every time slot would have the same max number of people. However, there are times where appointments are booked offline via sales team, and we would then have to manually remove one slot from online. Would be great if this function is available w/o having to fill in much details (i.e. to have an option to fill details to remove slot, or not to include details to remove slot).