I have an ASE File that I want to use to update an existing document with new colors. I know how to add this ASE file into indesign/illustrator already, but once I add it into indesign/illustrator, will it automatically update all the colors in that document to reflect the new color palette? Or will I have to manually change each color myself?
Once you open the ASE file in Illustrator, Photoshop, or InDesign, the colors that are there will be part of the ASE file, but new swatches will not. There is nothing automatic. You will need to save out a new ASE file (or use the same name to overwrite the original).
Use the panel menu in each app to save the selected swatches. You may also see other choices that are unique to the app and can only be used in that app.