Wrong player correctable error

[ChuckElias]

Ok, here's a sitch. Both teams are in the bonus. B1 fouls A1. The officials mistakenly allow A2 to shoot the one-and-one. During A2's first FT, A3 fouls B3. The FT is successful. The officials correctly rule a false double foul and clear the lane for A2's second FT. A2's second attempt is also successful.

Officials then have B3 shoot his one-and-one at the other basket. B3's FTs are both successful. A2 inbounds the ball to A1, but A1 fumbles it and the ball goes OOB.

At this point, (before the ball becomes live for Team B's throw-in) Coach B notifies the officials that A1 should've shot the original one-and-one. Officials correctly rule that the error can still be corrected.

Exactly what do you do to correct this error?