HONG KONG, Jan 13 (Reuters) - China Evergrande Group"s (3333.HK) main unit Hengda Real Estate Group has reached an agreement with bondholders to delay payments for a 4.5 billion yuan ($707.52 million) onshore bond, Hengda said in a filing on Thursday. The company had been seeking a six-month delay for redemption and coupon payments on its 6.98% January 2023 bond at a meeting with bondholders held Jan. 7-13. The putable bond gave holders the right to sell them back to the issuer early on Jan. 8.