Is it possible to change the function of mouse clicking a label without recycling the theme?

For example I have a label that when you click on it, it displays the Theme Popup. Now without recycling I want to be able to change it so when you click on it activates a different bang.

Hope that makes sense.

I assume you're using textedit or something like that to change the LabelOnLeftClick line in step.rc. After that do something like !execute [!reload][!labelrefresh] - !reload tells the litestep core to reload step.rc. !labelrefresh makes the label reread its (updated) configuration.
If you want a purely !bang driven solution (ie. without textedit) I suppose there could be a !changeclick !bang added to subclass.dll.

use mzscript's !varrun (varname). then somewhere you !varset bar !dothis and !varset bar !nowdothis.
then you have LabelOnLeftClick !foo, and perhaps either a *script start to set bar, or have bar in a varfile.

err, !foo would be a bang to !varrun bar. not the only way to do it, of course.

Thanks for the answers. I went with the !reload option as reload was already a part of this script. I don't know why I didn't spot this answer to begin with.