These 1 ) approving both changes in existing services and the establishment of new services---those are known as classification cases ; 2 ) adjudicating complaints from anyone who believes the Postal Service is not providing rates or services as required by law ; 3 ) issuing advisory opinions when the Postal Service proposes a substantially nationwide change in the nature of its services ; and , 4 ) our mostly recently assigned task , providing Congress with annual reports about the costs and revenues of international mail .
It 's necessary to issue advisory opinions when a nationwide change to the Postal Service is proposed .