Lerp movement in unity

I have four cornres on a plane(c1,c2,c3,c4),

I need to move the player(p1) to the particular corner of the plane. When I click on c1 the player(p1) should move towords c1, and when I click on c2 the player should move towords c2 and so on. But the problem is that the player should move towords the corner only once.that means the player can move towords the corner only once.

I have used Lerp movement in unity3d. enter image description here64053-lerp.png

If there’s just those 4 corners, maybe you could put in booleans that checks if the player has already been there?

Or you could use a list/array of transforms that incorporates each corner upon reaching it, and after that do a check that the corner is not in that collection before the player is allowed to go there?