1. In Administration> click Globally Change Records
2. Highlight Students, and click New Change
3. In the window that opens, expand the Attributes dropdown, and select Attribute that is listed directly below Attributes after expanding it. 
4. In the Operation dropdown, select Delete
5. In the subsequent fields and select the Attribute to delete in the Value dropdown
6. Click OK
7. Filter on the records to include on the Filters tab
8. Click Preview Changes to review the records that will change, or click Change Now