change in circumstances); United States v. Unger, 915 F.2d 759, 762 (1st Cir.1990); United States v. Fazzini, 871 F.2d 635, 643 (7th Cir.1989) (“Once the defendant has knowingly and intelligently waived his right to counsel, only a substantial change in circumstances will require the district court to inquire whether the defendant wishes to revoke his earlier waiver.”); Panagos v. United States, 324 F.2d 764, 765 (10th Cir.1963) (concluding that there were no facts or circumstances preventing “the initial waiver of the right to counsel, knowingly and intelligently made, from extending to and being fully effective at the time of sentencing” where only a reasonable amount of time intervened between the plea and sentencing); Davis v. United States, 226 F.2d 834, 840 (8th Cir.1955)
holding that defendants waiver of counsel when pleading guilty was an implied waiver as to any subsequent proceedings including sentencing four days later holding that defendants failure to obtain counsel despite opportunities to do so implied a waiver of counsel holding officers failure to obtain a written waiver from defendant did not render his oral waiver or subsequent confession involuntary holding that a defendants statements were voluntary after defendant initially refused to sign waiver but later initiated the contact with police and signed the waiver recognizing that courts will enforce waiver of appeal rights when waiver is knowing and voluntary