To transfer ownership, first find the correct patient on the search screen. Once you have found the patient, you click on the context menu for that patient (the three vertical dot menu). Once the menu opens you select "Change Ownership"
This will open the Change Ownership dialog, where you can select the new owner:
Your cursor will be in the auto complete which will help you find the new owner. Once you have selected the owner click save and the patient and their record will be switched to the new owner.