If the parameter is based on the location number, then you either have to hardcode the locations in a formula like this:
numbervar i;
numbervar j := ubound({?Location}):
stringvar x :=
for i := 1 to j do (
x := x + (
select {?Location}
case 123 : "London"
case 234 : "Paris"
case 353 : "Moscow"
) + ", ";
left(x,len(x)-2)
Or, if there are too many to hard code, add a subreport, create the same location parameter as in the main report, link the sub to the main report by linking the parameters to each other, and then add the location field to the detail section. You can collect the values in a variable if you want a paragraph style display versus a list display.
-LB