If you are the manager of Team and your team member has failed their assessment attempts, they will need to reset their course to take the assessment again. There are two ways to do this depending on the payment option of your Teams account.
Monthly subscription
If your Teams account is set up on the monthly subscription payment option, your team member can go back through the referral link (the same one they used to enroll their account) to reset their course.
Paid in full
If you have paid in full for a certain amount of usages when you created your Teams account, you would have to buy additional usages if all of your credits have been used. You will receive a new referral link which you should send to the team member who needs to reset their course.