From Longman Dictionary of Contemporary Englishunhitchun‧hitch /ʌnˈhɪtʃ/ verb [transitive] FASTEN/DO UP#to unfasten something that is joined to something else→ See Verb table
Examples from the Corpus
unhitch• When business was slow; the butcher allowed his girls and Amelia to unhitch the two horses from the traces and ride. 