This is all from memory, so forgive me if it’s vague in places. If you have access to it, use the WRKQRY command to work with the query definitions.
Select the query you want to change from the list and put option 2 next to it. You should get to a screen where you have a list of things you can work with, such as file definitions, selection criteria, sort criteria, etc.
At the bottom of the list (or second from bottom) is an option to change the output for the query. Select that and press Enter and you will work through a series of screens. One of those allows you to change the printer and outq for the query.
Hope it helps