What is the test for abuse of Rule 14?

We review the district court's decision for abuse of discretion. United States v. Sitton, 968 F.2d 947, 961 (9th Cir.1992), cert. denied, --- U.S. ----, 113 S.Ct. 1306, 122 L.Ed.2d 695 (1993). A district court abuses its discretion in denying a Rule 14 motion only if an appellant demonstrates clear, manifest or undue prejudice establishing that he or she was denied a fair trial. United States v. Catabran, 836 F.2d 453, 460 (9th Cir.1988); United States v. Escalante, 637 F.2d 1197, 1201 (9th Cir.), cert. denied, 449 U.S. 856, 101 S.Ct. 154, 66 L.Ed.2d 71 (1980).