ὑποστρέφειν

From LSJ

εἰ ἀποκρυπτόντων τῶν Μήδων τὸν ἥλιον ὑπὸ σκιῇ ἔσοιτο πρὸς αὐτοὺς ἡ μάχη καὶ οὐκ ἐν ἡλίῳ → if the Medes hid the sun, the battle would be to them in the shade and not in the sun

Source

Greek > English (Woodhouse Verbs Reversed)

(see also ὑποστρέφω): go back, turn back, turn round, turn sharp round, turn tail

Lexicon Thucydideum

convertere iter, to change one's route, 3.24.2, 4.33.2.