When is "too late?"

[NCASAUmp]

ASA SP

Yesterday, had a sitch that had me wondering...

Two outs, bottom of 7th, score is 14-12, and there's a runner on 2B. The next batter is known for knocking them out of the park, and he steps into the batter's box. There's some back and forth on the defense about whether they should put him on, and in the end, the pitcher says to me, "put him on."

As the runner gets to about 10 feet from home plate, the DC realizes that the other team has already hit their limit, and that it would be better to pitch to that batter.

Once I've already been informed of the intentional walk, can the batter be brought back to the plate prior to him reaching 1B?

My statement to the coach was, "no, coach, I was informed of the intentional walk, and I've already awarded him 1B."