Q: Can editors move a journal to a different publisher?
A: Only if they represent the owner of the journal (a foundation or university). If the publisher owns the journal it is unlikely they will agree to a move, which will not prevent a fresh start under a (slightly) different name.

A few case studies are discussed in the 2012 Notices of the AMS.

• Compositio Mathematica was published by Kluwer, but owned by a separate foundation, which chose to move to Cambridge UP.
• Topology is owned by Elsevier, so it had to change name becoming Journal of Topology, when the editorial board chose to move to Oxford UP.
• Mathematika is owned by University College London, which moved to Cambridge UP with help of the London Mathematical Society.