The Toolkit for Adagio is capable of changing a vendor or customer posted transaction date. I see that you own the Toolkit but not that particular function. You also need to enable this ‘date editing’ option in the Toolkit company profile because changing dates of posted transactions has to be done with care. For example, it doesn’t change the associated Ledger transactions. As Steve mentioned, a credit or reversal is the preferred method. The Toolkit method would be easier and cheaper over GridView Read/Write.