Ray,

Yes, I'm asking WHY it's required if all the details are remaining the same.And why can't Exchange mailboxes be migrated so all we have to do is rebuild Sharepoint? What's the difference between a P mailbox and an E mailbox? Does the new plan get a new billing account even though all the credentials are the same?

Also, is there an article somewhere that outlines all the steps needed to migrate plans?

"you would need to cancel your account and then sign up for a different one. After you sign up a new Office 365 tenant, you need to remove the domain in the tenant of Plan P "

I'm sure you mean cancel the P account AFTER setting up the E account otherwise how would you be able to migrate from the P account?

Hi mchv2.0,

For the difference between the Plan P mailbox and Plan E mailbox, you can refer to the service description of Plan for enterprise and Plan for small business.
http://www.microsoft.com/en-us/download/details.aspx?id=13602
http://www.microsoft.com/en-us/download/details.aspx?id=13779

For other questions like billing, you can contact Sales and Billings team. You can find their contact details of the following link.
http://onlinehelp.microsoft.com/en-us/office365-enterprises/ff652548.aspx

Thanks,
Ray Yang

Hi mchv2.0,

How are things going?

If you have any other questions or concerns, please do not hesitate to contact us. It is always our pleasure to be of assistance.

Thanks,

Ray Yang