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1. Reviews are automatically updated so long as commits contain the same Change ID. If your review has any findings, rebase the commits as appropriate, making sure the Change ID is preserved:

   Code Block
   $ git rebase -i HEAD~{num}

2. Re-push the changes:

   Code Block
   $ git review

   or:

   Code Block
   $ git push asterisk:{repo} HEAD:refs/for/master

   Warning
   There is a git/gerrit incompatibility between certain versions that may cause a review/push command to fail with "unpack failed: error Missing tree" when the commit was amended and only the commit message changed. To work around this error, add --no-thin to the push command.

Troubleshooting

git-review

...

sudo pip install --upgrade setuptools

on your command line

Problem: attempting to run git review results in "unpack failed: error Missing tree":
Description:  There is an incompatibility between certain version of git and gerrit that causes this error when the commit to be pushed was amended an only the commit message changed.
Solution:  Run git push manually with the --no-thin option:

git push --no-thin git push asterisk:{repo} HEAD:refs/for/master