As a general rule in PF Expert, only an Admin can delete another user. Also, an Admin cannot be deleted; their role needs to be changed to either a Manager or an Agent from their User Profile.
From the main Users list, right-click the user you want to delete and hit the Delete button. If this user has any data (listings, leads, owners or transactions) assigned to them, you will be notified in a pop-up box where you will need to re-assign all the resources to another user or specific resources to a particular user individually. Then, click the delete button to confirm.
Don't worry though, deleting a user will not delete all their assigned data. The only way to proceed with deleting the user is when you complete the re-assignment.
In the case where the user does not have any resources assigned to them, you will be notified as well in a pop-up box and you can delete them right away.
It is also important to note that only one user can be deleted at a time; multiple users' deletion is not supported as their data needs to be re-assigned.