This would be only with the use of macros possible which aren't recommended within the gui. An alternative could be to create several different charts and toggle with a button per variable their visibility (option within the tab layout).
Example: create a button (text: bar chart). Add an action to it: Actions > External > Set variable
Variable name for example 'vChart_Type', with value: Bar_Chart
Now in your bar chart go to the layout tab > Show - Conditional > vChart_Type='Bar_Chart'
This should do the trick; your chart is only visible when the variable vChart_Type is equal to 'Bar_Chart'
You can now create a second button with the same action, but with another value. E.g. Line_Chart
Now in your line chart go to the layout tab > Show - Conditional > vChart_Type='Line_Chart'
This should do the trick; your chart is only visible when the variable vChart_Type is equal to 'Line_Chart'
There are some more options you can use, for example a 'switch button' which evaluates the value of the variable first before changing it. This is done with an IF-function; plenty of examples here on the forum.
