To log into a different another Formplus account while signed into one already, it is advisable to;
Access the second Formplus from a private/incognito window or a different browser and sign in to the other account.
The other alternative is to log out from your currently signed in Formplus account and sign in to the other Formplus account. Logging into Formplus with two different accounts on the same browser will throw an error if changes are made and be saved. This error might cause you to lose your changes.
To log out, click on the First name icon at the top right of the dashboard and select the logout option from the dropdown list displayed as shown in the image below'