The unearned revenue is deferred revenue or cash that we have received for services and/or products that will be delivered in the future. If you are looking for the entries, then the entry would be to reverse the sales entry and increase the deferred revenue account. In other words, you would:
Credit Deferred Revenue
To answer your question, unearned revenue is a credit for the balance but you will need to debit the income statement (the revenue line) to decrease the revenue reported.