You can offer your customers the opportunity to renew their subscriptions at a discount. The Price Options Configuration page lets you configure a different discount percentage for each price option, as well as a range of days before and after expiry when the discounts are available.

You can use try the test transaction ID 6b8ab5e61e3b82ec75f83d281f7dc54f - but you will find that it's too soon to renew it at a discount because that transaction is valid until 2030.