This will depend on two things: when you made the changes and when the latest Siteimprove crawl occurred. Siteimprove crawls defined websites every seven days, therefore the dashboard report will take some time to update and reflect any changes you have made to your site.

You can login and view your Siteimprove Dashboard at any time, but the date of the next crawl is when your latest results will be displayed.

What you can also do is check your site using the Siteimprove Chrome Plugin, which should show your issues as fixed, even though this is not yet reflected in your Siteimprove dashboard report.