code: public void revertImplementation(Page page) {
          Integer previousImplementedVersion = getPreviousImplementedVersion(page);
          if (previousImplementedVersion != null) {
              saveImplementedVersion(page, previousImplementedVersion);
              savePreviousImplementedVersion(page, null);
          }
      }
docs: Sets the implemented version to the previous implemented version.
  
  @param page a {@link com.atlassian.confluence.pages.Page} object.