Hello forum. I have blue gum hardwood flooring in my house and it is in need of sanding and re-varnishing

I am 50-50 about doing it myself but my main reason for this post is to get advice on the colouring of it. It is much "redder" than I would like and was wondering if it is possible to tone it down after sanding to a lighter shade and how I go about obtaining this

Many thanks, Ralph

Do you want to darken the floor?
The color red will only change by using a black dye or pigment unless you bleach it. Bleaching will damage the lignin in the wood so I would not recommend bleach.
Some water-based poly-urethanes tend to lessen the red tones vs. a solvent type finish just by how they change the color of the wood when they dry. You will need to sand to bare wood and then try different finishes as samples.