Arrived to system in cool, went to indoor unit and found indoor coils frozen due to being low on R22. Informed manager and asked if she would like me to vacuum water that is in the drain pan and any that spilled over but water could drip from the ceiling as the rest of the coils defrost. Vacuumed water and Laid towels down to help capture any water from the coils. Ceiling is not dripping at this time but could continue to drip as rest of the coils defrost. Need to leave thermostat off.