You will need the Limited Write People permission to perform this action, at one or more of the member's campuses. It is campus-scoped, so a campus override can change it at one campus. See People for what the permission covers, and Campuses and organizations in Version 8 for how campus access works.
In One Church Software, family members are managed together from the family record. You can change a member's role, tag, or relationship there.
Edit a family member
Open the family member's profile.
In the Family card on the right, click the pencil icon (edit).
In the Edit Family window, make your changes, then Save.
What you can edit
In the Edit Family window you can:
Change a member's position using the Adult/Child dropdown.
Add an optional tag for a member, such as parent or friend.
Mark two members as married or in a relationship using the heart icon next to them.
Open a member's 3-dots menu (⋯) to View profile, Set as family manager, or Remove from family.
Add someone new with the Search to add a new family member box.
Use the Relationship Details section to describe how two members are related.
Tip: The family manager can edit other family members' profiles and is the family's main point of contact. Members at campuses you cannot reach are left out of the Edit Family window, and changing the whole family's campuses needs Limited Write People at every member's campuses.