If it's the master keyword you're talking about, it can take a few days for it to be approved. If you're trying to change the "related links," it's true that it doesn't always take. Sometimes you have to do it two or three times before it takes. Keep in mind that you should change them for each language, not only for English. Do the English, then do "Other" and it might fill in all the other languages for you, or sometimes it won't and you have to do each one manually. Of course if you can actually translate your related links into those other lanaguages that's great, otherwise just do them in English.