Is there a way to manually add an Affiliate referrer

I am using the affiliate plugin with prosites. Suppose the person signing up, their site doesn't give credit to the referrer.. is there a way to manually add?
Let's say the person who signed up was referred from talking with the affiliate and not using the link.... then they message me and tell me they referred "X" customer... now I need to add them to "X" as the affiliate referral