As these are not deciduous trees which lose their leaves in autumn they don't necessarily have a dormant period. However, autumn/winter is probably the best time to move them when the soil is likely to be more moist to stop roots and leaves drying out. As Bromsgrove has suggested, it's important to prepare the new planting holes before digging the plants up, and don't try to do this in freezing/frosty conditions. Make sure you water the plants in well in their new locations and keep the soil around the roots moist for weeks after replanting, even if it has been raining.