Reversal of a conviction based on ineffective assistance of counsel (IAC) requires proof that: (1) counsel's performance was deficient when measured against the standard of a reasonably competent attorney, and (2) counsel's deficient performance so undermined the proper functioning of the adversarial process that the trial cannot be relied on as having produced a just result. The Court must presume counsel's conduct fell within the wide range of reasonable professional assistance and accord great deference to counsel's tactical decisions. (In re Crew (2011) 52 Cal.4th 126, 150 (Crew); People v. Lewis (2001) 25 Cal.4th 610, 674 (Lewis).) If an IAC claim can be determined on the ground of lack of prejudice, a court need not decide whether counsel's performance was deficient. (Strickland v. Washington (1984) 466 U.S. 668, 697 (Strickland), Crew, at p. 150.) Because it is inappropriate for a reviewing court to speculate about the tactical reasons for counsel's actions, when the reasons are not readily apparent in the record, the court will not reverse unless the record discloses no conceivable tactical purpose. (Lewis, supra, 25 Cal.4th at pp. 674-675.) If the record sheds no light on the reasons for counsel's actions, a claim of IAC is more appropriately decided in a habeas corpus proceeding. (People v. Mendoza Tello (1997) 15 Cal.4th 264, 266-267.) To establish ineffective assistance of counsel as protected by the United States Constitution's Sixth Amendment right to counsel, "defendant bears the burden of showing that (1) counsel's performance was deficient, falling below an objective standard of reasonableness under prevailing professional norms, and (2) absent counsel's error, it is reasonably probable that the verdict would have been more favorable to defendant. (Strickland v. Washington (1984) 466 U.S. 668, 687-688; People v. Ledesma (1987) 43 Cal.3d 171, 216-217.)" (People v. Mays (2009) 174 Cal.App.4th 156, 171.) Tactical decisions by trial counsel, even if they prove to be unsuccessful, do not constitute ineffectiveness as embodied by the Sixth Amendment. In other words, to succeed on a claim of ineffective assistance of counsel, the defendant must demonstrate that (1) counsel's performance was deficient; and (2) the deficient performance prejudiced the defendant. (Strickland v. Washington (1984) 466 U.S. 668, 687.) As to prejudice, we inquire whether there is a reasonable probability that, but for the conduct of counsel, the result would have been different. (People v. Mincey (1992) 2 Cal.4th 408, 449.) As well, in reviewing such claims, we must exercise deferential scrutiny; we assess the reasonableness of counsel's conduct under the circumstances as they existed at the time of the maligned acts or omissions. (Ibid.) "Defendants have a Sixth Amendment right to counsel, a right that extends to the plea-bargaining process. During plea negotiations defendants are 'entitled to the effective assistance of competent counsel.' " (Lafler v. Cooper (2012) (Lafler).) Ineffective assistance during plea negotiations is not cured by a subsequent trial that is free from constitutional flaw. In the context of a defendant rejecting a plea offer, to establish a claim of ineffective counsel, a defendant must establish both that counsel's representation fell below an objective standard of reasonableness and that it is reasonably probable that, "but for the ineffective advice of counsel there is a reasonable probability that the plea offer would have been presented to the court (i.e., that the defendant would have accepted the plea and the prosecution would not have withdrawn it in light of intervening circumstances), that the court would have accepted its terms, and that the conviction or sentence, or both, under the offer's terms would have been less severe than under the judgment and sentence that in fact were imposed." (Lafler, supra, 566 U.S.; see also Missouri v. Frye (2012); People v. Alvernaz (1992) 2 Cal.4th 924, 936-938 (Alvernaz).) Once defendant has established that ineffective assistance of counsel caused him to reject the plea offer, the trial court must fashion an appropriate remedy. The "remedy must 'neutralize the taint' of a constitutional violation, , while at the same time not grant a windfall to the defendant or needlessly squander the considerable resources the State properly invested in the criminal prosecution." (Lafler, supra, 566.) Where the "offer was for a guilty plea to a count or counts less serious than the ones for which a defendant was convicted after trial, or if a mandatory sentence confines a judge's sentencing discretion after trial . . . the proper exercise of discretion to remedy the constitutional injury may be to require the prosecution to reoffer the plea proposal. Once this has occurred, the judge can then exercise discretion in deciding whether to vacate the conviction from trial and accept the plea or leave the conviction undisturbed." (Lafer, supra.) Ineffective assistance based on failure to call witnesses: A claim that counsel should have called additional witnesses at trial "'must be supported by declarations or other proffered testimony establishing both the substance of the omitted evidence and its likelihood for exonerating the accused. We cannot evaluate alleged deficiencies in counsel's representation solely on defendant's unsubstantiated speculation.' " (People v. Bolin (1998) 18 Cal.4th 297, 334, 956 P.2d 374.) Accordingly, "on direct appeal, a claim of ineffective counsel cannot be established by mere speculation regarding the 'likely' testimony of potentially available witnesses. We cannot assume from a silent record that particular witnesses were ready, willing and able to give mitigating testimony, nor can we speculate concerning the probable content or substance of such testimony." ( People v. Medina (1995) 11 Cal.4th 694, 773, 906 P.2d 2.) Therefore, where a witness whom the defendant contends should have been called did not testify, and the record contains no reference to any evidence that he or she might have presented, the appellate court cannot, without engaging in speculation, "'infer anything about its existence, availability, or probative force, or the probable consequences of its use at trial.'" Consequently, in such a case "there is no evidence to support defendant's claim of ineffective assistance in this regard." ( People v. Wash (1993) 6 Cal.4th 215, 269, 861 P.2d 1107.) Ineffective assistance of counsel -- in general To secure the reversal of a conviction based on ineffective assistance of counsel, a defendant must show (1) his counsel's performance was deficient when measured against the standard of a reasonably competent attorney, and (2) counsel's deficient performance so undermined the proper functioning of the adversarial process that the trial cannot be relied on as having produced a just result. The appellate court must presume counsel's conduct fell within the wide range of reasonable professional assistance and accord great deference to counsel's tactical decisions. ( People v. Lewis (2001) 25 Cal.4th 610, 674.) Further, because it is inappropriate for a reviewing court to speculate about the tactical reasons for counsel's actions, when the reasons are not readily apparent in the record, the court will not reverse unless the record discloses no conceivable tactical purpose. ( People v. Lewis, supra, 25 Cal.4th 610, 674-675.) If the record sheds no light on the reasons for counsel's actions, a claim of ineffective assistance is more appropriately decided in a habeas corpus proceeding. ( People v. Mendoza Tello (1997) 15 Cal.4th 264, 266-267, 933 P.2d 1134.)