Applying Coupon During Early-Bird Period

Hi Tuan,
We currently use early-bird discounts and would like to initiate coupons for specified registrants. Currently, both the early-bird and coupon discounts are applied during the early-bird period. Currently, during the early-bird period, we would like to only apply the coupon discount if a valid code is entered but apply the early-bird discount if no code is entered. Can this be done?

Thanks,
Tem