In his initial testimony, Cook testified that Stans said he (Stans) had lied to the grand jury investigating the Vesco donation. Cook admitted that he lied to the grand jury on April 19 and to the Senate committee on May 1. Cook also said that Stans called him on the morning of May 7, 1973, to discuss Cook's upcoming grand jury testimony. Cook informed Stans that he was changing his testimony to the grand jury and would tell the truth. When called before the Senate again on May 14, Cook said he changed his testimony again and told the truth.