Can I cover gloss with a mat product to get a mat finish?
I have travertine that was sealed using two different products - one mat, one gloss.
I would prefer a mat finish but I don't know if I can apply mat over the glossy areas and get a mat result?
Well, this is an interesting situation. It sounds like you put some products on the your floor to attain some sort of finish.
Exactly what I never recommend on any stone floor.
A stone professional can refinish the floor without using coatings that put a false finish on the floor.
To put a matte finish, honing powders can be used to put a uniform finish on travertine and polishing powders can be used to put a polished finish on travertine floors.
Using a gloss coating will only make matters worse. I've never heard of a matte finish chemical. This may have been a penetrating sealer that didn't leave any finish at all.
Now that there were coatings put on the floor, what you need to do is strip the floor with high alkaline strippers. These strippers may etch the floor during the process, where you will need to refinish the floors afterwards.
This is a very time consuming and costly project, not to mention the use of harsh chemicals.
I would call a natural stone professional to come help with the project as the process is too long for me to advise in this post.
I wish I could be more help.