I tried to uninstall Office 2013 through the Control Panel > Programs and Features > Uninstall applet. But it did not work. Right-clicking, selecting Change and trying to repair Office also did not work.
Then I came across this Microsoft Fix it that let you easily remove or completely uninstall Office 365 or Office 2013 suites and programs.
Download the Microsoft Fix It, exit all Microsoft Office programs and run the Fix It.
It will ask if you’d like to Apply the fix or Skip the fix and continue troubleshooting. To uninstall Office, I selected Apply this fix.
The uninstaller will run for a minute or two.
After a few minutes, the troubleshooter would have completely uninstalled Microsoft Office from your computer.
If you selected the Troubleshoot option earlier, you will be notified of problems found, if any.
Clicking on View detailed information will give you some more information about the problems.
You can download the Fix It from KB2739501 and run it to uninstall Office 2013 from your Windows 8 computer.