It is possible to discount bookings in back office by using an account promotion.
Account promotions need to be applied to the customer account, and this will then automatically apply the membership promotion. This is generally used for repeat customers / group bookings.
Within the promotions screen, set up a new promotion and apply this to whichever items qualify:
(Screenshot below from test system)
The promotion then needs to be applied to any customer accounts that you would like it to qualify for:
Before searching for the customer:
Link it to the customer:
