In order to change the owner of the web account please follow the steps below.
1. Log in to your Mindjet Web account 2. Go to the top right corner and click on the icon of a profile picture 3. Click on Account Management 4. In the drop down box select the name of the account 5. Click on the members tab 6. Select the member. 7. Click change role and select "Owner"
Only the current owner of the account can assign a new owner