As you change licenses on the General tab of either Users/Services, there are some effects you should be aware of:

💡Visible effects

• During Bulk Editing, as you add or remove users/services to edit, the property border colors change depending on the (mis)matching feature set. Clicking a property will change the color, e.g. from “Different (orange)” → “Equal (green)” → “Disabled (grey)”.
• As you made any changes on properties the the "Save" button becomes enabled. Saving changes is required before changing tabs, also because license changes has background effects (→ see below).
• After a license change is applied, Feature tabs become visible or are removed. On a mismatch between users, a tooltip will inform why tabs are greyed out, e.g. because licenses are missing for one user.

💡Background effects 

• Removing licenses works the same way as a License Downgrade. A removed license takes immediate effect (see note below) and can be assigned to other users / services.
• Adding licenses in bulk checks if your License Management has enough spare licenses to apply to all your selected users. A tooltip will inform when insufficient licenses are available.