How have courts treated a motion to substitute retained counsel before a sentencing hearing?

In People v. Munoz (2006) 138 Cal.App.4th 860, 869 (Munoz), the appellate court determined the trial court abused its discretion in denying a request to substitute retained counsel before a sentencing hearing. The case is instructive, but only because the facts there were different from this case. The defendant in Munoz wrote a letter to the judge over a week before his scheduled sentencing hearing, indicating his desire to discharge his retained attorney and asking for the court to appoint a new attorney for him specifically so he could file a motion for new trial. (Id. at p. 864.) The court discussed the matter with the defendant and his retained lawyer at the scheduled hearing, then trailed the matter several days, and allowed the defendant to submit additional materials detailing his concerns about his lawyer. The defendant submitted an additional six-page letter outlining his concerns. (Id. at pp. 864-865.) However, at the next hearing, the court denied the substitution request, essentially incorrectly relying on the need for a Marsden showing of incompetence, but then continued the sentencing hearing another month on the court's own motion to allow defendant to solicit supporting letters from family and friends to be considered for sentencing. (Munoz, supra, at p. 865.)