Number the rows, especially the end cuts. Remove enough rows of planks so you have room to work. When you get a few rows done, the existing planks may begin to get in the way, so remove more rows (numbered of course) and set them aside. If you have space, you could undo 1/2 the room when you begin. You would want to check how much expansion gap they left on the end cuts so you can duplicate what they did. Check that out before any removal. so you don't end up short...........I'm thinking tho, you aren't going to tackle this yourself? How much material was left over?