This card can be chained to the activation of a Flip Effect from a Flip Summon to negate the Flip Effect. It cannot be activated during the Damage Step, so if a Flip Effect Monster is flipped face-up when attacked you cannot chain “Royal Command” to negate its Flip Effect.
If “Royal Command” is active on the field both players may still Flip Summon monsters, but any Flip Effects are negated.