How to restain and varnish timber staircase

[nurseedward]

Hi everyone, Im new to this site.
I want to change the colour of my wooden staircase from tan to mahogany. It is very shiny and smooth and Im so afraid I will ruin it! How do I strip back the varnish easily (I hate sandpaper with a passion!), and what do I use to recoat?
Stain varnish combo
Or, stain, then use some sort of varnish coat separately?

Any advice would be very welcome. Thanks, Edward (Sydney)

[Master Splinter]

Strip to bare timber with sandpaper, sand to 150-ish grit, restain then revarnish. There goes your next ten weekends solid....

You could try overcoating with a tinted varinsh to shift the colour, but it may turn out horrible...test in a 'this will be the first to be stripped' place.