Say I want the 4th row of a very long table to be the repeating header row on subsequent pages. What I do is break the table into 2 tables. Cut the first 3 rows to the clipboard. Add a blank line (paragraph) above the remaining table and paste the first
3 rows back into the document above this blank line. Or, you can use the split table command.
Select the 3-row table, properties, table tab, text wrapping, around. Then grab the little plus sign at the upper left corner of the table and drag it into position to exactly merge with the top line on the table below. If you have trouble getting it just
right, use the Positioning dialog box to make slight adjustments.
Set the top row of the lower table to automatically repeat its top (header) row. It now appears to be a single table with the 4th row as the repeating header.