From Ground: If the old man banksia is currently situated in the ground, you should first water the soil around it to decrease resistance during the extraction process. Thereafter, using your garden shovel, dig a wide and deep enough circle around it so as to include the complete root ball. You should then lift out the plant carefully, ensuring you don't damage its roots.
From Pot: Start by watering the pot sufficiently. Wait for a few minutes to let the water soak in, then turn the pot sideways and gently shake it to let the old man banksia slide out along with the soil clump. If the plant is stuck, you may use a clean knife or a hand trowel to loosen the sides.
From Seedling Tray: To remove old man banksia seedlings from a tray, lightly water the tray first. Then, gently pry the root ball out of the tray using a spoon or your fingers, being very careful not to damage the young roots.