Merge pull request #4765 from gaurav-nelson/ForIssue4147

fixed issue 4147 and added alternative command for provided example.

Author: Gaurav Nelson

admin_guide/managing_projects.adoc

@@ -200,6 +200,13 @@ metadata:
 ...
 ----
 
+You can also override the default value for an existing project namespace by using the following command:
+
+----
+# oc patch namespace myproject -p \
+    '{"metadata":{"annotations":{"openshift.io/node-selector":"region=infra"}}}'
+----
+
 If `openshift.io/node-selector` is set to an empty string (`oc adm new-project
 --node-selector=""`), the project will not have an adminstrator-set node
 selector, even if the cluster-wide default has been set. This means that, as a
@@ -281,7 +288,6 @@ with this label will not have a maximum of project requests.
 to any user that doesn't satisfy the previous two rules. Because rules are evaluated
 in order, this rule should be specified last.
 
-
 [NOTE]
 ====
 xref:../admin_guide/manage_users.adoc#managing-users-managing-user-and-group-labels[Managing