Liddell-Scott-Jones

συναλλάσσω (sunallassō) to reconcile ^G:V

συναλλάσσω-άσσω,

  Attic dialect συναλλάσσωάττω, perfect συνήλλαχα [Refs 1st c.BC+]. etc.: 2 aorist passive συνηλλάγην [Refs]:—bring into intercourse with, associate with, δίκαιον ἄνδρα τοῖσι δυσσεβεστέροις [Refs 4th c.BC+]:—passive, have intercourse with, Ἑλένῳ συναλλάσσωαχθεῖσαν εὐναίοις γάμοις [Refs 5th c.BC+]

__2 reconcile, τινάς τισι [Refs 5th c.BC+]; τινας, opposed to διαλλάττειν, [NT+5th c.BC+]:—passive and middle, to be reconciled or come to terms with, make a league or alliance with, πρός τινας [Refs 5th c.BC+]: absolutely, make peace, [Refs 5th c.BC+]; μετρίως on fair terms, [Refs 5th c.BC+]
__II intransitive, have dealings with another, [Refs 5th c.BC+]; ἦ ξυνήλλαξάς τί πο; hast thou had any dealings with him, [Refs 5th c.BC+]
__II.2 enter into engagements or contracts [Refs 4th c.BC+][same place]; οἱ συνηλλαχότες the parties to a contract, [Refs 2nd c.BC+]: with accusative cognate, τοιοῦτον πρᾶγμα συναλλάσσωάττων [Refs 4th c.BC+]:—passive, to be the subject of a contract, [Refs 2nd c.AD+]

_{LSJ Scripture Refs: Acts.7.26}