To void an invoice by deleting any payments on the original invoice and creating a credit note from the original invoice follow the below instructions
From the BusinessMind home page click on the Sales link.
From the Sales Home page locate the View Invoices section and search for the invoice you want to create a credit invoice for.
Click on the invoice to open the invoice detail view.
If the invoice has any payments or credits attached to it you must now remove them.
Click on the payment link and choose the remove option and confirm.
Before proceeding be sure to make a note of the invoice date.
Click on the gear icon and choose the create credit note option.
This will create a credit note and populate it with all items from that invoice.
Change the Date to match the date of the original invoice.
Then Click the save button to save.
Now click the gear icon and choose the Allocate Credit option.
Allocate the credit to the original invoice and your all set