Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
Calchās, antis (gen. Calchae, Gell. ap. Charis. p. 50 P.; acc. Calcham, Pac. and Plaut. ib.; Calchanta, Verg. A. 2, 122; Val. Max. 8, 11, ext. 6; Stat. Achill. 1, 493; 2, 7; Calchantem, Cic. N D. 2, 3, 7; id. Div. 1, 40, 87; 2, 30, 63; abl. Calchă, Plaut. Men. 5, 1, 48; cf. Prisc. p. 702 P.; Ritschl prol. ad Plaut. Trin. p. 87), m., = Κάλχας, son of Thestor, the most distinguished seer among the Greeks before Troy, Verg. A. 2, 122; 2, 182; Ov. A. A. 2, 737.