I could able to remove the recent modified vertex of a feature using removePoint method of modify interaction, as well as using deleteCondition event of modify interaction. However, that is not what I am trying to achieve. The usecase for this this problem is as below.

I have modify interaction added on map. Now when user tries to modify a feature over map, I am highlighting the vertices, like this  

 if(this.modifyInteraction.features_.getLength() && this.modifyInteraction.features_.getArray()[0]){
           //Feature being modified
           let modifyft = this.modifyInteraction.features_.getArray()[0];
           let coord = modifyft.getGeometry().getCoordinates()[0];
           let foundIndex;
           for(var k = 0; k < coord.length; k++){
              if(coord[k][0] == rightClickedVertex.getGeometry().getCoordinates()[0] && 
              coord[k][1] == rightClickedVertex.getGeometry().getCoordinates()[1]){
                 foundIndex = k;
                 break;
              }
           }
           if(foundIndex && foundIndex > -1){
              modifyft.getGeometry().getCoordinates()[0].splice(foundIndex, 1);
              //nothing changes
           }
        }

I could able to remove the recent modified vertex of a feature using removePoint method of modify interaction, as well as using deleteCondition event of modify interaction. However, that is not what I am trying to achieve. The use case for this this problem is as below.

I have modify interaction added on map. Now when user tries to modify a feature over map, I am highlighting the vertices, like this 

 if(this.modifyInteraction.features_.getLength() && this.modifyInteraction.features_.getArray()[0]){
           //Feature being modified
           let modifyft = this.modifyInteraction.features_.getArray()[0];
           let coord = modifyft.getGeometry().getCoordinates()[0];
           let foundIndex;
           for(var k = 0; k < coord.length; k++){
              if(coord[k][0] == rightClickedVertex.getGeometry().getCoordinates()[0] && 
              coord[k][1] == rightClickedVertex.getGeometry().getCoordinates()[1]){
                 foundIndex = k;
                 break;
              }
           }
           if(foundIndex && foundIndex > -1){
              modifyft.getGeometry().getCoordinates()[0].splice(foundIndex, 1);
              //nothing changes
           }
        }