Because your Phoenix roebelenii has been outside getting direct sunlight all summer, it will have some adjustment difficulties when you move it inside. The primary problem is a dramatic reduction in light even if you can place it right in front of a very sunny, uncovered window, which you should. That doesn't mean it will die, but it will gradually lose lower fronds and not look as vibrant as it does now. In dry air, this plant is very prone to spider mites. A humidifier or a large pebble tray will help, but misting will not.
You will want to keep the soil moist, but it will use less water than it did when outside in sunlight and warm temps. Now is NOT the time to repot as everything will slow down now.
