1. Login to your Microsoft Online portal. (Administrator Credentials)
2. Click Admin.
3. And under Team sites and documents click Change permissions.
4. Point Grant Permissions make a left click on it.
5. In Users/Groups: type the name of the user you need to grant full control permissions to the SharePoint.
6. Under Grant Permissions click on the arrow and select Owners [ Full Control ].
7. To finish hit OK. Sam Dawsen / v-sadaws@microsoft.com