CORE allows editing of draft as well as finalized invoices (invoice details > Edit Invoice screen). You can make changes to the draft invoices and then finalize them or convert the finalized invoices into drafts and then edit them. Check CORE Help Center for details.
Typically, you edit the time and expense entries before or during the creation of the invoice, e.g., include or exclude entries, apply Write-Up/Down, etc. You can change the time and expense entries on an invoice after you create it provided the invoice has no payments attached to it or has not been posted yet. Check CORE Help Center for details. To edit your invoices, you no longer need to delete and recreate them.