Pretty basic question, but I've never done this so I'll have to ask. I need to cut out a section of 4" PVC and install a wye so that I can connect my new 3" drain line to the main line. I'm fine with going 3" to 4", but my question is how to fit the wye in the existing pipe. This pipe is 3.5-4 ft deep. I guess the logical thing to do is somehow dig around enough so that you could lift both sections of the main line enough to somehow fit the wye in, but I don't see this happening. That's going to be some serious excavation to be able to get a 4" pipe to budge any when it's 4 feet deep. What are my options? Thanks.