For a client we need to switch the endpoint used by our custom integration field. Unfortunately, the new endpoint uses different IDs for the same product than the previous endpoint. We do have a way to map the old IDs to new IDs, however, we were unable to make the changes in Prismic.
What we tried: the integration field was updated to the new URL and a sync was completed. The export functionality was used to obtain all documents as JSON. In these files, for each product, the integration field reference was changed to include the new ID. The changed files were imported into Prismic. The validation step in Prismic shows that the imported documents are correct. But after visiting the product in Prismic the integration field is empty when looking at the newly imported revision/release of that document. Prismic does recognize the new products, just not through the import function.