Roughly coincident with the birth of a child to the Duke and Duchess of Cambridge, Parliament is set to make changes to the Act of Succession, allowing females to be directly in the line. The problem is that countries other than the UK have the English monarch as their soverign heads - including Canada, Australia, and others.
Obviously, if they decided they didn't like, say, Prince Charles, I'm assuming they could disassociate themselves - but do they have any other recourse if they don't like the proposed changes?