Q: (from Greg)
Clarify the transition plan – if moving from E3 to Business Premium, what happens to Access and Lync? Does the customer need to uninstall and reinstall Office? Will they be rendered useless?
To see the differences between the Office productivity suite included with Office 365 Business and Office 365 ProPlus: http://office.microsoft.com/en-us/business/compare-all-office-365-for-business-plans-FX104051403.aspx
To switch from Office 365 ProPlus (included with Office 365 Enterprise E3) to Office 365 Business (included with Office 365 Business Premium), you will install the new plan and remove the old plan according to: https://support.office.com/en-US/Article/Switching-versions-of-Office-if-you-change-Office-365-plans-857dc33a-1efc-4ce7-ac3f-ef616314e27d