Hii @Kasey Shen, 

We have two possible scenarios

1. Hire date change 

When re-hiring an employee, we suggest creating a new Employee profile. This allows you to enter the new Hire date without affecting the previous one. It also ensures historical reports remain accurate and all data in the Employee profile is correct. Additionally, you can add a new onboarding template for the user.

If you create a new Employee profile, you can perform an import to transfer data to the new profile. You can download necessary documents from the old profile and upload them to the new one. To reuse the email, you'll need to modify it slightly in the old profile, as duplicate emails aren't allowed. Consider adding '123' to create a temporary email.

We also suggest setting up a new Employee information/Attribute section to record details like the original start date, original separation date, and a link to the old profile. Employees without access to the 'Status' attribute will only see the new profile, as the old one should be marked Inactive.

2. Hire date does not change

If you wish to keep the original hire date, you can update the current profile by changing the needed attributes (you could also add new Custom attributes with new information needed, for instance “original probation period” or creating one new “New probations period” and set a Reminder for this as well) and adding new work contracts to the Documents tab. 

For more information, please refer to this article:
How Do I Manage Employees Being Re-Employed In Personio?

Have a great rest of your day!

Best regards,