Rose bush

I have what I believe to be a shrub rose; it grows very large and dense and is absolutely full of buds and flowers small pink blooms in vast numbers constantly until November time. My problem is - it is right next to the garden path and overhangs the path so in the summer we cannot use the path and I end up having to prune away one side which spoils its appearance. I would like to move it at the end of flowering and was wondering when is the best time and how much root system do I need to maintain for it to regrow in its new position. I feel a large amount of root maybe under the lawn and path and hence will end up being cut off. Thanks for your advice in advance, Glenys