you should be able to move it down. Maybe the ride goes below ground slightly...so you would have to lower the ground, or take of ground collision first as the ride blueprints don't automatically adjust the terrain.
I had to uncheck global vertical snapping and it worked. I can now fine adjust the vertical position of a blueprint (ride with building) so that it sits on the ground in the correct position. With global vertical snapping enabled the vertical x key tool would jump from position to position and I couldn't get the right position.