Here's what I have come up with in the for loop, but I get a script error. Basically, the logic is: if address is null, try the next i, if it's not null, carry on to the GeocodeResponse.
let noRows = NoOfRows('Facts')-1;
for i=1 to $(noRows)
// let a=peek('Pt_FNAME',$(i),'Facts');
// let b=peek('Pt_LNAME',$(i),'Facts');
if IsNull ($address)) Then
//also have tried Next i;