During the lifetime of your campaign, you may run out of coupon codes to send to customers and need to upload a new batch.
How do I add new codes to an existing list?
Go to Campaigns > Coupons.
Find your list in the Coupon lists tab and click on the plus icon in the Actions column.
Upload a CSV file with all your unique coupon codes. They should be in the first column, with one code per row.
If instead of adding new codes you need to replace the existing unissued codes with new ones, see Replacing coupon codes