Yes you can! Simply go into the Matter Set-up by clicking on the '...' icon on the right-hand side of the matter
Or if you are viewing their Questionnaire, click on 'Options' then Set-up in the top menu bar.
The matter set-up screen will open. If you are a mediator, just ensure you choose the relevant party's tab.
Scroll down below the list of sections, and you will see this message.
Click on 'Want to reset access to the questionnaire?' This will close the set-up screen and a pop-up will appear confirming it has been done. You can advise your client to log in again and they can continue where they left off.