You can't edit or delete transactions included on a VAT Return.
To correct an error on your submitted VAT Return, reverse the transaction. Then re-enter it with the updated details.
For transactions included on draft VAT Returns, delete the draft VAT Return. You can then amend or delete the transaction.
To reverse the other payment, create the opposite transaction; a Purchase Other Receipt.
Any corrections that you make will appear when you create your next VAT Return.