Comment by vander_elst

I think the workflow in JJ is a bit different in this case, you can try to have a base commit `jj new -m 'base'`, then create an anonymous commit on top `jj new`, then make some changes in the anonymous commit and when you are ready to send out a PR/MR you squash `jj squash` or split `jj split` and squash what you need in the base commit.