There are two ways to modify the value of a variable:

frxReport1.Variables['My Variable 2'] := 10;

or

var

{ search for the variable }

Index := frxReport1.Variables.IndexOf('My Variable 2');

{ if it is found, change a value }

if Index <> -1 then

begin

end;

It should be noted, that when accessing a report variable its value is calculated if it is of string type. That means the variable which value is 'Table1."Field1"' will return a value of a DB field, but not the 'Table1."Field1"' string. You should be careful when assigning a string-type values to report variables. For example, the next code will raise exception "unknown variable 'test'" when running a report:

frxReport1.Variables['My Variable'] := 'test';

because FastReport trying to calculate a value of such variable. The right way to pass a string values is:

frxReport1.Variables['My Variable'] := '''' + 'test' + '''';

In this case the variable value - string 'test' will be shown without errors. But keep in mind that:

- string should not contain single quotes. All single quotes must be doubled;

- string should not contain #13#10 symbols.

In some cases it is easier to pass variables using a script.