Is there a way to have word modify a repeating header in subsequent insatnces, such as adding the text "(continued)" to all but the first instance of the header?
That's a feature that has been requested repeatedly for, oh, about 15 years. No dice.
The most common workaround is to put the "(continued)" in the header row in the first instance and let it repeat on all the other pages. Then, with the cursor in the paragraph above the beginning of the table, insert a text box or shape rectangle (which has
an opaque white background and has its border lines turned off) and position it to cover the unwanted "(continued)" in the first instance of the header.
Sweet, huh? NOT. For one thing, floating shapes don't always maintain position with respect to text. If editing of preceding text forces a page break just before the table, the box will be on the wrong page and the table header won't be hidden.