Situation 1.  
The employee's check has not yet been cashed by the bank.
1.  Void the check and delete the payroll calculation.
2.  Adjust the cause of the overpayment on the employee's compensation tab. 
3.  Recalculate payroll for the employee, and issue the check again as normal.

Situation 2.
The employee would like this corrected on their next check.
1.  Create a deduction for the employee to be taken out of their next check.

Situation 3.
The employee has been terminated or will not have another payroll calculation, but has already deposited the check.
1.  Create a deposit adjustment in the Payroll bank to record the payment back from the employee. 
2.  Adjust the employee's W2 amounts with a historic entry.