ASN's and Invoices can be re-analysed (and then re-uploaded) in bulk by selecting the orders on the dashboard and then right clicking and choosing 'Reanalyse' from the menu. 

You should use this feature when you have made a change to a shipment or invoice and need to resend it to the retailer.

Note to upload a specific invoice or ASN you can open the order, got to invoices, then right click and choose 'Reanalyse' from the menu. 

Please view the attached video demonstration