How to reinstall tribes through steam?

I bought both the game and the tribe expansion, however challenges are not working correctly and the engine display bug is affecting my installation. I would reinstall the tribe expansion but I can’t find the patch in steam or on my computer where would it be located?

Love GSB btw.

Did you buy them both through steam? In that case you can uninstall and reinstall tribes through steam.

Yes bought both through steam, the tribes expansion must patch the original base installation, it works on a different computer if I transfer my information over. It must be my computer. Thanks for the help.