You can only delete Users with a Draft/ Invitation Sent/ Invitation Expired Status.

To delete the User, 

1) Login to your Board.Vision portal as an Administrator*.

2) From the left navigation menu, select Users.

3) Select the Username.

4) In the View User Basic Information page, click on Delete.

5) Once a Delete User window pops-up, click on Confirm.

*This feature is available depending on your access level.