To re-onboard a returning employee, you can do the following:

If the majority of the employees onboarding data is correct, you can reactivate the employee's profile, and then the user can change any incorrect details through self service.

If the user needs to be fully re-onboarded, and their past Workforce data is not needed, the easiest solution would be to send the onboarding to the same email and create a new user. For this you will need to unlink the deactivated profile and remove their email address and phone number, otherwise this will block the new onboarding.

If the user has not already completed the onboarding, you can simply re-activate their profile, cancel their first onboarding invitation, and send it again on their staff profile.