Update docs with PMC steps to amend KEYS. (#384)

diff --git a/docs/release_manager_setup.md b/docs/release_manager_setup.md
index 8256776..3fb1bed 100644
--- a/docs/release_manager_setup.md
+++ b/docs/release_manager_setup.md
@@ -100,6 +100,22 @@
 
 The commands to export your key and append it (depending on your PGP client) can be found at the very top of the [`KEYS`](https://dist.apache.org/repos/dist/release/openwhisk/KEYS) file itself, and are also replicated below:
 
+> **Steps for PMC member to amend KEYS file**
+  ```
+  # checkout svn repo if necessary
+  ./tools/checkout_svn.sh
+
+  # amend KEYS file./stagingArea/svn_release/KEYS
+  cd ./stagingArea/svn_release
+  vi KEYS # or whatever editor you prefer
+
+  # sanity check your changes
+  svn diff
+
+  # commit
+  svn commit KEYS
+  ```
+
 #### GPG Example (recommended)
 
 Apache recommends [GNU Privacy Guard (GnuPG)](https://www.gnupg.org/), an open-source, OpenPGP compatible implementation.