What changes does perry want to make to his initial statement to the police?

Dick and Perry make official statements, and Perry revises his confession to read that he (Perry) pulled the trigger on all four victims (this, he confides, is done not out of concern for Dick but out of respect for Dick’s beleaguered parents). Dick and Perry’s advocates arrange for a psychiatric evaluation of the two men, which is performed by a young doctor named W. Mitchell Jones.