Penal Code section 1018 permits the withdrawal of a plea. "This section shall be liberally construed to . . . promote justice." (Pen. Code, 1018.) to withdraw a guilty plea, a defendant must show, by clear and convincing evidence, good cause. (Pen. Code, 1018; People v. Fairbank (1997) 16 Cal. 4th 1223, 1254, 947 P.2d 1321; People v. Castaneda (1995) 37 Cal. App. 4th 1612, 1616-1617; People v. Nance (1991) 1 Cal. App. 4th 1453, 1456.) Good cause to withdraw a plea is shown if the defendant did not exercise free judgment in entering into the plea. (People v. Cruz (1974) 12 Cal. 3d 562, 566, 116 Cal. Rptr. 242, 526 P.2d 250; People v. Castaneda, supra, 37 Cal. App. 4th at p. 1617; People v. Huricks (1995) 32 Cal. App. 4th 1201, 1208.) Pleas may be set aside if defendants are unduly influenced to accept a plea because their counsel is obviously not prepared to proceed (People v. Young (1956) 138 Cal. App. 2d 425, 291 P.2d 980), or the defendants represented by counsel entered into the pleas as a result of fraud or duress. (Pen. Code, 1018; People v. Cruz, supra, at p. 566; People v. Huricks, supra; People v. Dena (1972) 25 Cal. App. 3d 1001, 1008, 102 Cal. Rptr. 357.)