Our company obtains forms from corporations all over the country (usually pdfs), that we then convert to .png and place into Word 2016 in order to place our custom mail merge fields in the correct spots on the form. We have almost a thousand of these forms in .doc and .docx format. Currently, our custom mail merge fields are populated from our database in SalesForce, but we will be changing to new software in the coming months that will inevitably contain different mail merge fields. Same information, just a different field name.



Assuming that the new software won't be able to map the old fields, is there a way to update the old custom fields to the new custom fields in bulk without going into every Word document and updating every field individually?