If they are fast growing confiers, like leylandii, then I think most people would suggest digging them up and throwing them away.
Fast growing conifers can very easily get out of hand and soon you can have a massive tree that is hard to maintain, takes over the garden, and sucks all the moisture out the ground.
I live in a house with a long garden, and next door (right up to our fence) is a huge Thuja tree, higher than our house.
The brances overhang over garden, the roots suck all the moisture out the soil, and the shade covers all our garden.
The house is rented so nobody is interested in pruning it, though we prune our side.
So think carefully whether you DO want large conifers in your garden, or if you would rather get rid of them and plant something else.
ps. searching on "Moving conifers" in Google does give various sites giving advaice.