EXHIBIT 4 HELMERICH & PAYNE, INC. AMENDMENT NO. 1 TO RIGHTS AGREEMENT This AMENDMENT NO.1, dated as of December 8, 2005 (this "Amendment"), to the Rights Agreement, dated as of January 8, 1996 (the "Rights Agreement"), is entered into between...Rights Agreement • December 12th, 2005 • Helmerich & Payne Inc • Drilling oil & gas wells • Delaware
