Water your plant a couple of days before transplanting. After receiving the Mandevilla, let them acclimate to their new environment for a couple of weeks before transplanting. Use a 2 inches bigger pot for a patio. Place a piece of screening at the bottom of the container over the drainage hole to secure the soil and allow to drain. Use a well-draining indoor potting mix with perlite to help with drainage. Add soil to the bottom to elevate the root ball. Lift the plant and release the roots against the existing planter. Use a clean knife or garden trowel to wedge between the grower pot and the soil to loosen. Inspect the root ball. Notice if there are any dead or rotting roots and trim them off with sterile pruners. If the plant is rootbound, loosen the roots to alleviate continued encircling. Ensure the plant is sitting about 1 inch below the edge of the pot to avoid water spillage. Add more soil and backfill around the sides by tamping down. Fill up to the soil line but not over. Water thoroughly, leaving the soil damp but not soggy. If settling occurs, add more soil. Water well to dampen the soil and let drain. Place them in full to part sun (4-8 hours).