Is there any way for a Medium PC to wield a 2-handed sword in one hand?

I have a player in my game that has chosen to wield a Greatsword, a 2-handed weapon. As a Fighter, this is within the rules. However, he has asked if he can wield it 1-handed by somehow giving it the Versatile property.

He’s fine having to wield it two-handed if need be for now, but he’s interested in knowing if he can wield it one-handed later. He doesn’t want it for the Duelling or Dual Wielding feats — just “rule of cool” reasons.

RAW, is there any way this can be achieved? Either now, or through character advancement?