Update a guideline about Owners-Override

The CL updates the guideline per discussion on
[email protected].

Bug: None
Change-Id: Ib04194afc376765c60d74b09745c19ca25b29a3f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3218841
Commit-Queue: Kentaro Hara <[email protected]>
Reviewed-by: Bartek Nowierski <[email protected]>
Reviewed-by: Avi Drissman <[email protected]>
Reviewed-by: Scott Violet <[email protected]>
Cr-Commit-Position: refs/heads/main@{#931795}
diff --git a/docs/code_reviews.md b/docs/code_reviews.md
index 24b4dc7..59b4ce2 100644
--- a/docs/code_reviews.md
+++ b/docs/code_reviews.md
@@ -176,22 +176,27 @@
 have this capability. The power to use Owners-Override should be restricted 
 as follows:
 
-  * Active sheriffs can set Owners-Override only on changes needed for 
-    sheriffing (e.g., revert, reland, test fix).
-  * Release Program Managers can set Owners-Override only on changes needed 
-    for releasing (e.g., revert, reland, test fix, cherry-pick).
-  * Large Scale Change reviewers can set Owners-Override only on changes 
-    about the approved Large Scale Change.
-  * Global approvers can set Owners-Override only on mechanical changes 
-    associated with their API changes. For example, //base/OWNERS can set 
-    Owners-Override only on mechanical changes associated with //base/ API 
-    changes.
+  * Active sheriffs can set Owners-Override only on sheriffing CLs (e.g.,
+    revert, reland, test fix).
+  * Release Program Managers can set Owners-Override only on sheriffing CLs and
+    CLs needed for releasing (e.g., cherry-pick).
+  * Large Scale Change reviewers can set Owners-Override only on sheriffing CLs
+    and CLs about the approved Large Scale Change.
+  * Global approvers can set Owners-Override only on sheriffing CLs and
+    mechanical CLs associated with their API changes. For example,
+    //base/OWNERS can set Owners-Override on mechanical CLs associated with
+    //base/ API changes.
   * Chrome Eng Review members can set Owners-Override on any changes to help 
-    with cases that cannot be handled by the above groups. However, please 
-    use one of the above groups before asking Chrome Eng Review members.
-  
+    with cases that cannot be handled by the above groups and expedite CLs
+    when LSC is too heavyweight.. However, please use one of the above groups
+    before asking Chrome Eng Review members.
+
+When you need Owners-Override on sheriffing CLs, please reach out to the
+Active Sheriffs and Release Program Managers first. If none of them is
+available, please send an email to [email protected] for help.
+
 Note that Owners-Override by itself is not enough on your own CLs. Where this 
-matters is when you're sheriffing. For example, if you want to revert or 
+matters is when you are sheriffing. For example, if you want to revert or 
 disable a test, your Owners-Override on the CL is not enough. You need 
 another committer to LGTM the CL.