There are two attempts at a run out whilst batsmen are running. The first attempt is not out but leaves one of the bails on the stumps - the other on the ground. Taking another run the second run out attempt at the same end with only the one bail in place is made but can this be given out?
Yes, it can be out, and the bail is not even necessary. Law 29, The Wicket is Down is clear on this situation.
29.2 One bail off
If one bail is off, it shall be sufficient for the purpose of putting the wicket down to remove the remaining bail or to strike or pull any of the three stumps out of the ground, in any of the ways stated in 29.1.