I’m currently editing “Celebration” by Kool & The Gang, but the tempo is not uniform throughout. Is there way, possibly using Beat Finder to convert pieces to uniform tempo?
Audacity’s tools for changing the speed / tempo are listed here: http://manual.audacityteam.org/man/index_of_effects_generators_and_analyzers.html#Make_the_sound_faster.2C_slower.2C_lower_pitched_or_higher_pitched
Which one to use depends on whether you need to change both tempo and pitch or just tempo, and on whether you need to make a progressive (sliding) change or change in steps.
Audacity does not have tools to automatically make the tempo uniform. You would need to adjust it manually, though for a record that sold many millions, I’m surprised that you need to.