Rule 770 Unless the interests of justice otherwise require, extrinsic evidence of a statement made by a witness that is inconsistent with any part of his testi…

If someone testifies in court, and you want to show they said something different before, you generally need to give them a chance to respond to that earlier statement. This means asking the witness about the contradicting statement while they are still on the stand, so they can explain or deny it.

If you did not ask the witness about the statement during their testimony, you can still bring it up later as long as the witness has not been fully dismissed from the case. This gives the witness a fair chance to address the contradiction before the trial moves on.

The basic idea is fairness. A witness should not be contradicted by an outside statement without getting a chance to explain themselves. Courts can make exceptions if the situation calls for it, but this is the general rule.