Transplanting Garlic

When to transplant garlic seedlings in Montana? Established plants exist; want to share existing plants with friends.

It is not the usual practice to transplant garlic plants, so I am not sure what the effect of doing so would be on the harvest. Normally, you divide the bulbs to get more plants and plant those. If had to transplant garlic, I would try to do it as soon as it is possible to dig the ground in spring.