Content Analysis module allows you to run an in-depth page audit of any site's page and evaluate how well it's optimized for its target keywords.
To change target keywords for an analyzed page, simply go the Page Audit Settings > Manage Mapped Keywords:
And edit the list of keywords - delete any by clicking on x or add new ones hitting Enter after each word/phrase, then click Map Keyword(s):
The app will map the new keyword list to the page and will automatically re-run content analysis for it - allow a few moments for the app to gather and analyze the new competitors found for the new target keywords.
Alternatively, you can manage pages' keywords directly in the Keyword Map - unmap/remove any with the right-click or add any new ones; yet you'll need to hit the update icon to analyze the page anew: