Hi Chiranthi, when you mentioned the system prompt indicating that changes can't be made, did you process the paycheque through Direct deposit (DD)?
If you processed the paycheque through DD, please note that once the deposit has been sent to Electronic Funds Transfer (EFT) for processing, it can no longer be stopped.
The timing of the deposit typically depends on the funding schedule associated with your account. If the funds have already been deposited into your employee's bank account, you have a couple of options. You can either arrange internally with the employee to return the money or submit a request for a reversal.
For guidance on the reversal process, please follow the steps provided in this article: Reverse a direct deposit in QuickBooks Payroll.
If, however, you used a different payroll service to process the paycheque, you can refer to this article for detailed instructions on how to delete or void the duplicate paycheque: Delete a paycheque in QuickBooks Online.
If you have additional questions or need further assistance, feel free to reply here.
