a path switch game

i'm trying to make a game in which player switch path on tap vice versa.

But in my case i use

 while (distance<1.0f) 
         {
             if (TouchInput.IsPlayerUp == true) 
             {
                 Vector3 sDist = spline.GetPoint3D01(distance);
                 Vector3 sDis2 = detuSplineScripts.GetDistanceSplineBelow().GetPoint3D01(distance);
                 
                 player.transform.position = sDist;
 isUp=true;
 }else
 {
 if (isUp==true) 
                 {
             //        distance  = TouchInput.SplineBelowDistance;
                 player.transform.position = rayCasting.hitting.point;
                      lenghtOfHitPoint = rayCasting.hitting.point;
                 //    Vector3 normalizedV = new Vector3();
                     normalizedV.x =  lenghtOfHitPoint.x / detuSplineScripts.GetDistanceSplineBelow().GetLength();
                     normalizedV.y =  lenghtOfHitPoint.y / detuSplineScripts.GetDistanceSplineBelow().GetLength();
 isUp=false;
 }
 }
             distance+=Time.deltaTime*speed;
             yield return 0;
         }

it switches the path but not the picture like some time it move far from player or -far from player