To create a duplicate object by flipping it, use this this nifty tip. It requires you go to Tools > Customization and under Customization in the Options panel, choose Commands. Click on the Search icon and search for Flip, and Horizontally, then Vertically. Add those two icons to your Property bar or Toolbar. Or, you can go via the Menu: Image > Flip or Menu: Object > Flip. 

Tip provided by Stefan Lindblad, CorelDRAW Master, Illustrator, Graphic Designer & Artist.