How to switch user for WebLogon
If you ever connected to your SharePoint or O365 with one user you can use WebLogon authentication mode without need to enter any credential data. In this case ReplaceMagic is simply using already Windows stored user credentials.
In case that you want to change user, this is not possible as WebLogon will always pull credentials from Windows so to be able to switch user, you will need to sign out from current user and that can be done over https://myaccount.microsoft.com/ where you'll need to click on "Sign out everywhere":
This might take some time (not longer than 60 minutes) but after sign-off is completed when you go to ReplaceMagic and try to connect via WebLogon you will need to enter user credentials. Of course, if you later want to use standard user, just sign-off this temporary user using same approach.