Changing VAT on a previously VAT reconciled invoice - how to?

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I have just discovered that VAT was missed off a bunch of import invoices, which have already been included in previous VAT returns.  My question is, now I have copies of the invoices showing correct VAT breakdowns (which are within the 4 year amendment window) should I just edit the original invoice entries, or should I delete them and put on new entries?  I'm not sure which will allow the VAT to be claimed correctly on the next VAT quarter?