OK to reposition a 90 degree sweep of Schedule 40 conduit after it's been glued?
I would really try to avoid placing intentional stress on the PVC pipe to get it into position. 

Instead you should find the part of the pipe that is relatively straight where a cut and rotation of the pipe on its center axis will correct for the misalignment at the end. Then cut open the pipe and glue in a coupler to allow for the rotation.

The rope should be no problem. Tie on some more rope at the existing end and then when you cut the pipe do so in a manner that you do not cut off the rope. Once the pipe is open pull the extra rope down toward your cut area and open the knot so you can thread on the new coupling fitting. Then rejoin the knot and pull the rope back through to the end. Re-glue the joint with the rope inside the fitting.