When you first register a songwriter with Songtrust, we ask you if you are already affiliated with a Performing Rights Organization (PRO). The reason we do this is because if you are already affiliated, we need to generate and send out an LOD on your behalf.
In order for us to collect royalties your musical works have generated, we need to first inform PROs and other rights societies that you are giving us the right to collect your royalties for you. That is essentially what a LOD does - it grants us, Songtrust, the administrative rights for yourself and your publishing entity (if you have one) the ability to collect on your behalf. An LOD does not grant us ownership of your work. Once right societies have received your LOD we can begin the registration process for your works worldwide.
Below is an example of what an LOD could look like -