Is it valid for a divorced couple to reconcile if their marriage was consummated and they were divorced before consummation?

The ruling on divorce after the marriage contract differs based on whether a valid khalwa (private seclusion) occurred between the spouses. If khalwa did not occur, the spouses cannot return to each other except with a new contract and a new mahr (dowry), because a non-consummated marriage is irrevocably dissolved by a single pronouncement of divorce. However, if a valid khalwa did occur, it is considered equivalent to consummation, and the husband retains the right of rajʿah (revocation of divorce) as long as the wife is within her ʿiddah (waiting period). If the ʿiddah ends without revocation, then a new contract becomes necessary.