Can a defendant withdraw his guilty plea and enter a not guilty plea?

Defendant appealed, contending he was denied the right to a speedy trial. We held this issue was not generally cognizable on appeal following a guilty plea. However, when defendant tendered his plea, the trial court erroneously assured him he could reserve his right to appeal the speedy trial issue and issued a certificate of probable cause. Accordingly, we reversed the judgment to permit defendant an opportunity to withdraw his guilty plea. (People v. Bradley (Sept. 8, 1982, 3 Crim. 11759).) Defendant withdrew his plea of guilty and entered a plea of not guilty.