how to handle navigation.PopModalAsync()

I have a listview when tapped it will open up a page using navigation.PushModalAsync().

I used customrenderer so that the Textcell in listview will change color using

cell.SelectedBackgroundView = new UIView{BackgroundColor = UIColor.FromRGB (11, 38, 59)};

so when i pop the the what should I do so that I can change the cell back to the original color?

thanks