See the image below.

There are several ways to do this, including one that alters reality.

This is the recommended method I use, even though it is a few steps.  I want to void cheque 305 to ACME Novelty

1) Open the Payments modules and select the vendor.

2) Select Include Fully Paid Transactions from the toolbar icon marked with a red arrow or on the Payment menu.

3)  I use the cheque number with CR, Rev, Void or other designation as needed.  The image indicates CR but in this case I would use Void

4) Use the date voided, not the original date of the cheque.

5) Enter the amount beside the invoice(s) that were paid on that cheque.  Also include the discounts originally taken.  Note this first invoice listed has an amount owing of $0.00.

6) This step should be last.   First check the Journal entry report on the Report menu to make sure the money is going back into the bank.  Then Post if it is correct.

Then you can reissue the cheque as normal.  It is sometimes worthwhile to put a stop payment on the original with the bank.

I do not use the Reverse button on the toolbar (option on the Payment menu) because it alters the reality of the original cheque that was cut in the Vendor's historical reporting.  This above method shows the full history of the reversal and reissue of the cheque in the vendor's historical reporting.