The court properly exercised its discretion in denying defendant's application for assignment of new counsel, made as jury selection was about to commence. After receiving a suitable opportunity to be heard, defendant failed to establish good cause for such a substitution ( see People v. Sides, 75 NY2d 822). Defendant's vague and conclusory complaint about his attorney amounted to nothing more than an assertion that the attorney was "interrogating" and "not taking a liking" to his client. Furthermore, counsel went on to provide effective assistance at the trial, without any further complaint from defendant.