Go to Edit>Replace and place your mouse insertion point in the "Find What" box, making sure it is at the very start. Now push the space bar once. In the "Replace with" box push the space bar twice.
OzGrid Business Applications
You are going about it the hard way. Merely increase the size of the row height for all rows to be included in the report.
Not sure if you solved your problem with the double spacing, the responses didn't seem to help as I interpreted your problem.
Solution I would use.
Put a dummy column in to left or right of rows to be double spaced, insert odd number count, 1 3 5 .... down the rows, pull(copy) the count down as many rows as you have. Then add even numbers under the odds in blank rows below the information. Now select all of the information you want to double space and including the dummy rows of odds and evens. Sort the information by the dummy column in ascending order.