Vault owners differ from admins in that owners cannot be removed from a vault via the admin quorum. The owner of the vault is the first admin to pair their device to the vault, thus generating the underlying vault wallet keys.
To reassign vault ownership, go to Vault Settings > Users, find the admin you want to assign as the new vault owner, click the 3-dot action menu and select Assign Vault Ownership.
To confirm the assignment, click Change Vault Owner. The selected admin replaces the current owner as the owner of the vault, and the current owner becomes an admin.
Reassigning vault ownership is a vault action that requires admin approval based on your quorum settings.