As you can see below there are multiple ways to access the Record Sharing button. Whilst you have a patient record retrieved you can click on the record sharing button on the toolbar (if you have that button on your toolbar) alternatively you can select record sharing node in the administrate tree. As shown below

The above dialogue will then show. You will not be able to view the patients record from other SysmOne organistaions without Sharing in and other SystmOne organisations will not be able to view your record without sharing out. The above box must be filled in appropriately, once completed select ok.