How to change the endpoint for animation when the animation started

//Set Location
ContentControl.HorizontalAlignment = System.Windows.HorizontalAlignment.Left;
Canvas.SetLeft(ContentControl, 3);

//Define Strat And End Animation
myDoubleAnimation1.From = 0 ;
myDoubleAnimation1.To = this.ActualWidth ;
myDoubleAnimation1.Duration =TimeSpan.FromSeconds(1);
sb.Duration =TimeSpan.FromSeconds(1);

Storyboard.SetTarget(myDoubleAnimation1, ContentControl);
Storyboard.SetTargetProperty(myDoubleAnimation1, new PropertyPath("(FrameworkElement.RenderTransform).(TranslateTransform.X)"));
 

sb.Children.Add(myDoubleAnimation1);
//Event For Finish the Animation
sb.Completed += _Completeds;

// Begin the animation.
sb.Begin();