In this post the focus is on upgrading SQL Server 2008 R2 SE SP1 to SQL Server 2008 R2 EE SP1. Below are the screenshots that will guide you through the upgrade process.
1) In the first step, locate the SQL Server enterprise edition folder and double click on setup.exe
2) In the installation center go to Maintenance and click on Edition upgrade
3) Hit OK in the below screen if everything goes well. Click on the show details button and fix any errors in case of any errors.
4) Hit Next and enter the enterprise key in the product key page as shown in the below screenshot
5) In the license terms page check the “I accept license terms” and click Next button as shown below
6) Select the instance you want to upgrade the edition and click on the Next button as shown below
7) Click on Show details button to see the edition upgrade rules and resolve any errors if anything needs to be fixed and then click on Next button as shown below
8) Now click on Upgrade button as shown below
9) Once the upgrade is completed successfully you will see the below screenshot
Click close button if all looks well. In case of any failures the errors are written to eventviewer or summary.txt located at
C:\Program Files\Microsoft SQL Server\100\Setup Bootstrap\Log\
Go through the summary.txt and fix the errors and retry the upgrade process as mentioned above.
Hope this helps!