Parascending or Parasailing is a fun activity and has even turned into a sport to some degree but only if done safely (equipment, conditions, training, judgement). Using a Canopy specifically designed for this is the better choice.
Modifying a Round Parachute for Parasailing is another choice but increases the risk significantly. But if the modifications area done intelligently by qualified people then those risks can be managed or reduced.
Modifying or using a RAM Air canopy for this is even more dangerous and is not recommended.
I have personally been involved in parascending using both a PC and a Parafoil. The PC we simply kited on a fixed line anchored to a fixed object in strong but steady winds and we never went very high. The Parafoil we towed behind a truck and we were lucky we lived. A year later someone else tried to follow our example with different gear and someone nearly died.
It's tempting to want to put that old gear to some other use. Tie a weight to it and fly it as a kit but stay firm on the ground is my opinion. Mike Lanfor
D13540
AFF-I/T-I, S/L-I/IAD-IE, CCD (not current), PRO, Video, MFF #9229, Army S/L JM (Master Parachutist), Private Pilot ASEL and sUAS