After a query containing host variables has run (you have entered values for the host variables when prompted), the host variable values are saved. This allows you to re-run the query without being prompted each time.
It you need to change the values of the host variables, use the Parameters command from the Query menu. You can also use this command to preset the values for the host variables so that you are not prompted at run time.
To change or preset host variable values:
The Enter Host Variable Values dialog box is displayed containing all of the host variables for the current query, if previously run or previously specified.