Thayer's
STRONGS NT 2644: καταλλάσσωκαταλλάσσω; 1 aorist participle 
καταλλαξας; 2 aorist passive 
κατηλλάγην; properly, 
to change, exchange, as coins for others of equal value; hence, 
to reconcile (those who are at variance): 
τινας, as 
τούς Θηβαιους καί τούς Πλαταιεας, 
Herodotus 6, 108; 
κατηλλαξαν σφεας οἱ Παριοι, 5, 29; 
Aristotle, oecon. 2, 15, 9 (p. 1348b, 9) 
κατήλλαξεν αὐτούς πρός ἀλλήλους; passive 
τίνι, to return into favor with, 
be reconciled to, one, 
Euripides, Iph. Aul. 1157; 
Plato, rep. 8, p. 566 e.; 
πρός ἀλλήλους, 
Thucydides 4, 59; but the passive is used also where only one ceases to be angry with another and receives him into favor; thus 
καταλλαγεις, received by Cyrus into favor, 
Xenophon, an. 1, 6, 1; 
καταλλάττεται πρός αὐτήν, regained her favor, 
Josephus, Antiquities 5, 2, 8; and, on the other hand, God is said 
καταλλαγῆναι τίνι, with whom he ceases to be offended, to whom he grants his favor anew, whose sins he pardons, 2 Macc. 1:5 2Macc. 7:33 2Macc. 8:29; 
Josephus, Antiquities 6, 7, 4 cf. 7, 8, 4 (so 
ἐπικαταλλάττεσθαι τίνι, 
Clement of Rome, 1 Cor. 48, 1 [ET]). In the N. T. God is said 
καταλλάσσειν ἑαυτῷ τινα, 
to receive one into his favor (
A. V. reconcile one to himself), 
2 Corinthians 5:18f (where in the added participles two arguments are adduced which prove that God has done this: first, that he does not impute to men their trespasses; second, that he has deposited the doctrine of reconciliation in the souls of the preachers of the gospel); 
καταλλαγῆναι τῷ Θεῷ, to be restored to the favor of God, to recover God's favor, 
Romans 5:10 (but see  
ἐχθρός, 2); 
καταλλάγητε τῷ Θεῷ, allow yourselves to be reconciled to God; do not oppose your return into his favor, but lay hold of that favor now offered you, 
2 Corinthians 5:20. of a woman: 
καταλλαγήτω τῷ ἀνδρί, let her return into harmony with (
A. V. be reconciled to) her husband, 
1 Corinthians 7:11. Cf. Fritzsche on Romans, vol. i., p. 276ff (who shows (in opposition to Tittmann, N. T. Synonyms, 1:102, et al.) that 
καταλλάσσω and 
διαλλάσσω are used promiscuously; the prepositions merely intensify (in slightly different modes) the meaning of the simple verb, and there is no evidence that one compound is stronger than the other; 
διαλλάσσω and its derivatives are more common in Attic, 
καταλλάσσω and its derivatives in later writers. Compare: 
ἀποκαταλλάσσω.