Fill the new pot halfway with general-purpose potting soil. The pot itself should have drainage holes in the bottom and come with a removable saucer that sits underneath the pot.
Place the new pot and the original pot that still houses the plant on a piece of newspaper so you can collect dirt later. Insert a hand spade between the pot and the soil to loosen the plant.
Tip the plant on its side and gently pull it out of the old pot by its base. Knock the old soil off the roots.
Lower the schefflera into the new pot. Fill the pot the rest of the way with the potting soil, until it is planted at the same depth it was in the original pot.
Water until the soil settles. Set the plant in a warm, bright spot out of direct sunlight. Throw away the newspaper and the soil that spilled onto it.