I am remodeling my kids bathroom on the second story and wanted replace the existing tub with a shower pan. We ripped out the tub and found two plumbing vents that come up from the 1st story. They have a slight bent outward just above the floor board to go around the joist then they go back into the wall. This wasn't a problem with tub since the tub had some empty space that accommodated them. These will obviously not work with a shower pan. How should I reconfigure them? Can I drill holes into the joist? This happens to be at the end of the joist toward the exterior wall of the house. Would be really grateful for any advice you can provide.