When the plant is root-bound and ready to repot (early spring before growth starts), obtain a 2" bigger container in diameter and slightly deeper than the existing planter. (A bigger pot will eventually cause overwatering and a slower time for the soil to dry out.)
Trim off any dead, damaged, or diseased leaves or stems.
Carefully lift the vines and prop on top of the container to protect the hanging branches. Another set of hands may be advantageous for this process.
Use an indoor container mix that is well-draining mixed with one-third peat moss and one-third perlite. Add soil to the bottom to elevate the root ball.
After watering an hour before repotting, lift the plant and release the roots against the existing planter. Inspect the root ball.
Notice if there are any dead or rotting roots and trim off with sterile pruners. If the plant is rootbound, cut through the roots to alleviate continued encircling.
Ensure the plant is sitting about 1" below the edge of the pot to avoid water spillage. Add more soil and backfill around the sides by tamping down. Do not cover the current level of soil on the plant but add soil up to this level.
Water thoroughly, leaving the soil damp but not soggy. Add more soil after watering if the soil settles around the edges.