Moving dahlia location
You must wait until the current plantings have "rebuilt" the necessary strength in the tuberous roots to bloom again. What this translates to is after the frost in fall when the plants die back. If your location does not regularly reach the low 20's freezing weather, you can leave them int he ground until spring. Whenever, dig the plants carefully, shake off as much soil as possible, allow the tubers to dry for a few days and then store them in a frost-free, dry and somewhat dark place. Some people use a box of wood shavings or sawdust to put around the tubers to better avoid any rotting. Large clumps of tubers on one plant should be divided. You can consult any good source of information on perennials to find out how this is done and when. Sunset Western Garden Book has an excellent chapter on dahlias, and there is information on growing dahlias at extension.oregonstate.edu/publications. Search on "dahlia". When spring arrives, after the last frost dig holes at least a foot deep, place the tuber and fill the hole about 1/4th full. As the shoots grow in the warming weather, add more soil gradually until you reach the ground level. Incidentally, Sunset recommends a lightly shaded area rather than full sun for dahlias. Your previous question to Ask an Expert seems to indicate that you have such a location. Perhaps there are other factors causing the low bloom. When did you last dig and divide, for example? Are you feeding the plants properly? (Too much nitrogen, for example, causes green growth at the expense of blooms.) We strongly suggest you consult some good references for a through understanding of this beautiful addition to your flower garden.