First strip off any sealers, wax coats or other protective finishes on the current surfaces, you cannot restain them… you will need to strip them down to bare wood first.. secondly you cannot use red stain over brown stain… you'll get a mixed blotchy result… so in short to achieve your goal, you need to strip it all off first… then use the red stain…

HINT: consider priming it with an oil base primer and then paint it with exterior grade, high quality red paint… either flat, semi, satin or gloss sheen…