If you are doing the checklist via a browser, as soon as you have answered at least one question a new icon will appear in the Progress dialog box on your browser. Click and your checklist will be closed with a status “In progress”. Click on the “Verify now” button to open it again and continue.
If you are doing the checklist via the Mango mobile app, then click on the “back” button – this will open a dialog asking you if you want to save progress to date, or discard the data you have entered thus far – select the “Save” option. You checklist will be closed with the status “in progress” and can be found under the “In progress” tab.