If you do not have Helping Hands, be careful not to touch your soldering iron. The board can be held at an angle if this is easier.

While it may be possible to do a partial replacement, the remaining capacitors will fail. Do it once and change the entire set. Refer to this guide for soldering tips: How To Solder and Desolder Connections.

Move in a workspace with ventilation or use a fume extractor. Once in an appropriate workspace, desolder the old capacitors. Heat up the leg to remove it from the board.

After removing the capacitors, clean up the old solder with a desoldering braid Lift it with the iron when removing it.