Can you Move from an Office 365 Enterprise Plan to a Midsize Business Plan?

The short answer is, yes.
The long answer is that it will require a lot of work on your behalf.

The new Office 365 midsize business plan is very similar to the E3 plan (bar some advanced features which most users probably won’t need anyway) without the more expensive price tag attached to it; for UK users this is £9.80 per user per month as compared to £15 per user per month… if you have a lot of users the cost adds up very quickly.

The problem with Microsoft plans (and this has been a problem since the birth of Office 365 as I remember it clearly – perhaps BPOS also had the same issue?) is that if you want to move between different price ‘bands’, it simply isn’t supported by Microsoft.
Moving from an E3 to an E2 plan for example is completely fine. You just purchase some E2 licenses, go to the user properties and uncheck the E3 license and check the E2 license. All the data migration is done automagically in the background. Nice and easy.

Unfortunately the midsize business plan is (as I was told by several Office 365 representatives) classed as a ‘completely different’ product and apparently doesn’t work the same way as the other enterprise plans.
Personally I find this really silly because the description on the Office 365 web-site for the midsize plan states:

Best for companies with fewer than 250 users that want everything in Plan E1 plus Office as a subscription

You just buy some midsize business licenses and switch your users over. Now you’re probably thinking “it can’t be that easy right?” – sadly you are right. It’s not that easy. In fact, it is no where near that easy.

Below are the steps e-mails to me by a member of the Office 365 technical support team (ignore the references to the E1 plan):

Steps to Follow

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Provided Best efforts for this issue

• To switch plans, you need to cancel your account and then sign up for the plan you want. In order to move between the two plans, you would need to cancel your account and then sign up for a different one.

For detailed information, you can refer to the link below:
www.microsoft.com/…/faqs.aspx

Given this situation, you need to sign up a new E1 trial account. If you would like to move data from E1, you’ll need to migrate this manually.

You can follow the steps below:

1. Backup the current mailbox data to your local drive by exporting PST files:
http://support.microsoft.com/kb/287070

2. Sign up E1 account.

3. Remove your custom domain from current E1 account, and verify it to new E1 account.

Help article about how to remove a domain:
http://onlinehelp.microsoft.com/en-us/office365-smallbusinesses/gg549195.aspx#bkmk_removel
Verify a domain at any domain name registrar:
http://onlinehelp.microsoft.com/en-us/office365-enterprises/gg584188.aspx

4. Create new users for E1 plan subscription.

5. Import PST files to your new E1 account:

http://support.microsoft.com/kb/287070
office.microsoft.com/…/helppreview14.aspx

So there you have it folks. To move from an E or P plan to the new midsize business plan which I foresee a lot of organisations wanting to do, you have to backup all your user’s mailboxes and SharePoint data, delete your company domain from the Office 365 account, sign-up for a completely new Office 365 account, re-verify the company domain (could take up to 72 hours don’t forget), re-create the users, import user mailboxes back, import SharePoint sites & data back and hope that it all works. Oh and now that I think more about it, don’t forget all your Office 365 customisations in PowerShell as well as re-doing the active directory synchronisations.

Good luck… you’ll need it!