After witnesses are cross-examined at trial, the lawyer who offered the witness is allowed a chance to conduct "redirect" examination. During redirect, the lawyer can ask the witness questions that will allow him to explain any troublesome answers he gave during cross-examination.
As in most jurisdictions, the scope of redirect in Illinois is limited. The lawyer conducting redirect is not allowed to ask questions about issues that were not covered in cross-examination. In fact, the scope is even more limited than that: the lawyer may only ask questions about new matters that were covered in cross-examination. The witness, in other words, must do more than simply repeat answers he already gave during direct examination.
The judge conducting the trial has discretion to vary these rules and can allow a lawyer to ask new questions on redirect that the lawyer forgot to bring out on direct. One author suggests that a judge in this situation should forbid the questions, but allow the lawyer to recall the witness after the examination has been completed for the purposes of going into the new matters. See Hunter, Trial Handbook for Illinois Lawyers (7th ed.), at Section 31.1. According to Hunter, such a procedure "increases the orderliness of the proceeding by adherence to the rule that the examination is limited to the scope of the preceding examination, without restricting counsel in his right to bring out relevant testimony."