Programmatic modification of update center URL

Dear Group

Is there a way to programmatically modify the URL of a saved update
center as available via Tools->Plugins->Settings ? My alternative route
here is to make the change via an update of my module (which registers
the update center), however I'd like to give the user the option to do
this (in this unique case) by just running a particular action. Any
ideas will be greatly appreciated.

Best regards,
Ernest