With my Mircosoft Office 365 upgrade complete, I started reevaluating my subscription choice: I’ve had a Small Business account since Office 365 first opened its virtual doors a few years back, but since then Microsoft has added some additional subscription offerings. And now I’d like to upgrade my account to Office 365 Small Business Premium.

Doing so isn’t straightforward—you can’t just click an Upgrade button somewhere and give Microsoft some additional money—but once you realize what’s really happening here it’s not that difficult.

See, Office 365—excluding the recently released Office 365 Home Premium offering, which frankly should have been given a different name—is a subscription service that targets businesses of all sizes. So Microsoft offers a variety of plans that target different user needs. Each plan comes with whatever set of functionality and a commensurate cost.

In a small business, it’s conceivable that each user would be licensed for the same plan, perhaps the Office 365 Small Business offering I used originally. This is a simple set up that mirrors the simplicity of the business itself.

But in larger businesses, especially enterprises, there are going to be a wide range of users, each with different needs. So an enterprise might purchase multiple licenses of different types and assign them based on need. Some users would receive only web-based access to Exchange, SharePoint, and Lync perhaps, while others would also receive Microsoft Office. An admin or group of admins would simply assign the available licenses accordingly.

The thing is, all business-oriented Office 365 subscriptions work the same way. So even a small business could, if needed, purchase different plans for different users. You may have a few users that only need access to Exchange, SharePoint, and Lync on their PCs, phones, and via the web. And you may have a few that also need access to the full Microsoft Office suite. The former users could receive Office 365 Small Business  (P1) plans ($6 per month) while the latter could get Office 365 Small Business Premium ($150 per year or $15 per month).

In my case, I have a single Office 365 Small Business (P1) account that is tied to a custom domain. And what I want to do is “upgrade” that account to Office 365 Small Business Premium, gaining access to five installs of Office 2013 at an additional cost of $78 per year.

Here’s how you do this.

From the Office 365 Admin Center, navigate to Licenses (or Licensing in the enterprise versions of the product). Here, the Subscriptions view provides a look at which Office 365 subscriptions are available to your company. For my single-use Office 365 Small Business account, this resembles the following:

Office 365 Enterprise is a bit different, but the theory is the same:

Since I’m upgrading my own account, however, I’ll stick with the Small Business interface.

The first step is to purchase a new plan. To do so, click the Purchase Services link. Here, you’ll see a list of the available plans. (Again, what you see here will differ between the Small Business and Enterprise versions of Office 365.)

Scrolling down the list a few interesting options are available, key among them two Office 365 Small Business Premium options, one a year subscription ($150) and one a monthly subscription ($15). To add that plan to your account, click the appropriate Add button and work through the purchase wizard.

When you’re done, you can return to the Licenses UI in Admin Center and see that you now have two subscriptions attached to your account. In my case, this includes the pre-existing Small Business (P1) plan and the new Office 365 Small Business Premium (I went with the annual version).

The next step is to move users between the plans. I only have one user, so I just need to move him (me) from Office 365 Small Business (P1) to Office 365 Small Business Premium. You do this in Users & Groups (Users and Groups in Office 365 Enterprise). Here, select the user you wish to move to see which plan they’re associated with (or licensed to) and which other plan(s) is available.

To make the change, I simply unselected Microsoft Office 365 Plan 1 and selected Office 365 Small Business Premium.

After saving the change, and if necessary repeating this process for any other users you want to move over, the next step is removing the old plan (P1). To do so, click on the plan in Admin Center, Licenses, Subscriptions and then click Cancel this subscription in the next screen.

You’ll be prompted with some important dates regarding the expiration of the plan and data removal, though the latter isn’t a concern if you’ve replaced it with a different plan as I’ve done. Then, the Subscriptions view in Licenses will be updated to note the pending subscription plan cancellation.

If you’ve made the change I have, you may want to install Office 2013 now as well, since that’s a big part of the Office 365 Small Business Premium subscription. To do so, visit the Admin Center and click the Software tile in the Getting Started pane. (If it’s not available, click Return to the Getting Started pane under Setup.) Then, click Set up your software.

Enjoy!