How to change the Hours of a Service ...

[Candlestore]

I have a service as a Candle Class.  Has a set fee for this class and I want to change the Hours from 6:30 pm  till 8:30 pm to 5:30pm till 7:30pm for the winter.  I see no where on how to change or edit the Service Times for this item.  I can change the Discription but not the Appointment setting.  How would I accomplish this?  My Business hours I can edit but the appointment which is After hours I am unable to  locate this.   Any help would be appreciated.