how do I update the supply chain file if something changes in my company

You make changes in the chain dossier itself, not in the questionnaire

You process a change in one place: in the chain dossier. You adjust the source data — the number of employees, the address, a new certificate — and every list that is filled in afterwards uses the new value. So you don't need to go back to old, already submitted lists to correct them; they remain as they were submitted to your customer's portal. Only future answers change with it.

Some changes affect only one answer — for example the number of employees after a reorganization. Others immediately affect multiple answers at once: a new location flows through both the countries where you are active and possibly in the statement of employees per country. What matters is the distinction between a factual change (something has changed) and a correction (it was entered incorrectly). For a correction, it is useful to also check whether previously submitted lists with the incorrect value are still pending somewhere with a customer — you can assess this yourself, because only you know which portals that are.

Why the dossier remains the source, not the list

The chain dossier is set up as the single point from which all answers come, precisely to prevent the same change having to be made in ten places. For data that are required to be recorded, such as the statutory name or the registration number from the Trade Register Act 2007, the trade register is in any case the formal source — a change there must first be processed by the Chamber of Commerce, and you then take that value into the dossier. For certificates and policy choices, such as an ISO 27001 status based on the control measures in Annex A, there is no external registration requirement: you update that yourself as soon as the certificate changes or expires. The system never confirms itself whether a change is correct; you do that yourself per answer, with yes or no.