Remind them that NOBODY can convert them and the fact is, while annoying (and to be honest, one reason it took me so long to convert) those who try to convert Jews are few and far between. I remind those in my family or friends who say the same thing that there are WAY more important issues than someone talking to them about Jesus.
You converted from Judaism?? Did someone actually convert you or did you do it on your own?? Just curious.