You can update guardian types in bulk, or from the guardian profile in the Linked Students section. You can see more information on what a Primary Guardian is and how this is different from Legal Guardians here: Assigning family as Primary or Legal Guardians
You'll need the Student Profile: Guardians: Administer permission to edit guardian types. If you don't have the permission, you'll need to ask your admin team to give you permission using these instructions.
Go to Students > Parents & Guardians > Bulk Update > Authorised to Collect or Guardian Contact Details.
Use the filters to select the relevant Academic Year and choose the year group or form you need to edit in the Students Who Are... section.
Click on any guardians in the list that you want to change. In the slide over that appears, click Edit in the top right.
Make your changes to the Primary guardian option. Click Save Changes.