If you have an auto-renewing subscription, you won’t be able to redeem a coupon code while your subscription is active.
If you’ve purchased a one-time Pro subscription that does not auto-renew, you can redeem your pro coupon code by heading to the Pro page in your JioSaavn app. Simply click on the "Redeem Now" option and continue with the redemption. After a successful completion, the subscription days will be added to your account and you'll be able to enjoy all subscription features for an extended duration.
For folks on iOS devices, head to any Android device or the website to redeem your coupon code.