Change the query parm before forward

[Lim Hock-Chai]

is there a way to change the query parm in the request before forward it?
 
In my struts config file, I've a initialization action.  If say the order item 
sequence# is missing in the query parm, I need to change it to default to the 
next item sequence # before it forward to the actual form.
 
thanks.