You can change the value of parameters in the Init of the form only. You can use object parameter instead. See Re: Passing Array by Reference to a Form vfp6 Thread #659071 Message #659629.

>Hi,
>
>In my main form I'm calling a MESSAGE form and I'm passing 2 date parameters by reference (Start date and End date). My problem is that I need to change the values of my two parameters in my MESSAGE form.
>
>In my MESSAGE INIT I have defined my 2 parameters, however I don't know how to change the value of my parameters in my MESSAGE form to affect the value in my calling form?
>
>Thank you