You will need to move as many of the roots as you(and several friends, maybe?) can handle. Should wait until it is dormant to move, but you can do some things now. Select a relocation site. Partial shade, dappled shade, morning sun is best for nore flowers. Dig a hole twice as wide as the rootball you are moving and about as deep, ammend the soil if you wish and return the soil to the hole.
Determine the size of the rootball you can move and outline a circle around the plants stem(s). Using a shovel, go around the plant and sink the shovel vertically as deep as it will go, until you have completely encircled the plant.
Water it deeply, add 4" of mulch if necessary and retire!
After frost and the leaves have fallen off, then move it.
Dig as deeply as possible underneath the plant, until it is free. Using a sheet of heavy plastic, slide the rootball onto it and drag it to the new location. Open the new hole and slide the rootball in, leaving the soil level on the rootball about 2" higher than the surrounding soil, to allow for settling. Backfill around the rootball, using water to settle the soil. Mulch and water deeply. Check once a week, if no rainfall, for soil moisture 4-5" down below soil level. If dry, water deeply.
During the winter, if you have extended periods without rainfall, check to determine if watering is necessary.
You will also need to monitor moisture requirements for at least one year after moving it, until the roots become well established.
I have moved some(with a lot of help!), from a private to a public garden, that were so large, a winch was necessary to load them. They bloomed the following year as if nothing had happened.
Some sources recommend pruning off about one third of the total plant when moving it, but I never do that and so far have had good success (knocking on wood!)
Good luck and lift with your legs, not your back!
Rb