In the Overview / Multi Plan View, you can extract a day from your multi-day session to become a separate single session. Just click on the further options icon (the three vertical dots) under the day-session’s name, and select the option ‘Extract’. The extracted session will now be a separate session, accessible from your workspace and from the list of your most recently modified sessions on your Homepage
Please note that in order to extract a day, you need to be either the owner of each session involved, or have team admin rights if the affected sessions are in a team workspace.
In case you accidentally extracted one of your day-sessions from your multi-day session, you can still merge it back into your multi-day session.