[exim] Problem with forwarding and reply-to header

Welcome i have a small problem i read the list and found no answer my clients keep having email messages rejected because of spf filter on two of the biggest email companies. So i heard i need to change To and reply to header so the message contains only destination address so i t looks from this To: angel554@??? "angel554@???" to this To: angel554@???. Please help, but do not discuss if spf is right or wrong.