The Allocate on Agent Address button is only enabled in the South Carolina module. South Carolina allows you to process a file which includes two sets of addresses. One address that represents the insured risk and one address that represents the agent writing the policy. When the non-taxable report is loaded, you may reallocate the policy to the agent address.
You may also choose the Allocate on Agent Address option by right-clicking one a South Carolina report or by going to Tools>Allocator on Agent Address.
For more information, please see the South Carolina help topic.