hardwood stairs

[tomh]

You cannot stain through a polyurethane or lacquer finish without stripping or sanding. You may be able to even the color by applying a product like Minwax wood finish which is a stain and polyurethane mixture. Don’t expect dramatic color changes, but it may even things out. Try it on a a less conspicuous area first if possible. The variation in color may be due to the wood, or uneven application of stain, and may be noticable only to you. Another coat of clear urethane may be sufficient to hide the variation.

Be sure to sand lightly using a 120+ paper and clean with solvent to promote adhesion and smooth final finish.