Remember that a Row Format can be used in more than one statement.  To see if this row definition is used in other statements, go to General Ledger and click on the Design Statements super tab.  You should be viewing a list of the Statements.  If not, click on the binoculars button on the toolbar.  Read down the list of Row Formats and see where else this Row Format might be used.

If you want to add the line to all the Statements that use that Row Format:
  1. Click one of the Statements and then click the Row Format tab.  
  2. Select the line above the line that you wish to add by clicking on it. 
  3. Then click on the 'New' button at the upper left of the window (The sheet of paper icon).  This will insert a new blank line which you can populate with description, format, formula and print control.
  4. If the line created with a row number that will cause it to display in the wrong location, just edit the row number to a number that will place it correctly.
  5. Hit save and then the refresh button if needed to settle it into numerical order.

If you only want to add the line or row from ONE of the statements, then you will have to make a copy of the Row Format first by clicking on the Create/Copy Format button and then follow the above instructions to add the line to that format.

You will then need to update the Statement record with the name of the new copied Row Format.