Learn English – Should “no longer” have a hyphen

Hyphen and dash are at least three distinct characters, and the hyphen is the shortest.

• Hyphens “-” are primarily used in compound words (a 20-year-old co-ed) and when a word is broken at the end of a line (which explains why word breaking is called hyphenation). Hyphens are always very short, narrower than most letters. There is never a space between the hyphen and a word fragment that it joins (though there may be a space on one side in constructs like “pre- and post-conference activities”).
• En-dashes “–” are mostly used to express a range (1932–1945). They are sometimes used as super-hyphens (a Los Angeles–New York flight). In these uses, there is no space before or after. They are so named because they are as wide as a lowercase “n” in most fonts.
• Em-dashes “—” are sentence punctuation — often parenthetical — as shown in this sentence. They are at least as wide as an ”m”, occasionally even wider. There is no consensus as to whether to surround them by spaces.
• Another similar character is the minus sign. It is typically about one en wide and thicker than a hyphen or dash, but this is dictated by the choice of mathematical font which can be chosen separately from the main text font.
• There are many more somewhat similar characters and other uses of these characters; Wikipedia has a list as well as a lot of minutiae on these characters and their uses.

Both are possible, though re-rate is more transparent and thus easier on the reader. And of course you could simply say "change rating" or "rate again", as you just did.