It sounds like the author isn't really interested in named branches, but rather postpone the push of his work-in-progress that's on the default branch. You don'

It sounds like the author isn't really interested in named branches, but rather postpone the push of his work-in-progress that's on the default branch. You don't need anything fancy for that, and certainly not rebase. Mercurial has so-called anonymous branches, so all he needs to do is 'hg update' to the commit preceding his work on feature A, start work on feature B (will result in two heads on the default branch) and then push only those changes by specifying the -r flag to push.