Wpf - how to change design (position of elements) of UI

Hi guys, please how could I change the position of the elements in the UI, or choose a different design when the application loads?

It could be done using User Controls for each design, but the bad thing about this solution is that the same code will be repeated and I do not want that.

Please what would be the best practices to achieve this, it should be noted that the controls must have a name to use it in the code.

Thanks in advance.

Summary: This is what I want to achieve

<Grid.ColumnDefinitions>
    <ColumnDefinition Width="{Binding LeftButtonColWidth}"/>
    <ColumnDefinition Width="{Binding RightMainPanelColWidth}"/>
</Grid.ColumnDefinitions>

I Wish: <Grid design ="{Load DesignN}" ...>