WordNet records no synonym and no antonym for reorder. It is the only member of each of its synsets, which is common for technical, taxonomic and single-sense vocabulary — there is no other English word that means the same thing. The broader and narrower terms below are the useful relations in that case.
Counts are distinct word forms across every sense. A synonym that appears under three senses is counted once here and shown three times below, under each sense it belongs to.
assign a new order to
make a new request to be supplied with
“The store had to reorder the popular CD several times”
Synonyms, antonyms and the broader and narrower relations for reorder come from Princeton University’s WordNet. Full sources and licences.
a repeated order for the same merchandise
“he's the one who sends out all the new orders and reorders”