Bring in the Patch interface.
diff --git a/openstack/cdn/v1/services/requests.go b/openstack/cdn/v1/services/requests.go
index 4e4c37c..8593eaf 100644
--- a/openstack/cdn/v1/services/requests.go
+++ b/openstack/cdn/v1/services/requests.go
@@ -275,6 +275,12 @@
 	appropriatePath() Path
 }
 
+// Patch represents a single update to an existing Service. Multiple updates to a service can be
+// submitted at the same time.
+type Patch interface {
+	ToCDNServiceUpdateMap() map[string]interface{}
+}
+
 // ToCDNServiceUpdateMap casts an UpdateOpts struct to a map.
 func (opts UpdateOpts) ToCDNServiceUpdateMap() ([]map[string]interface{}, error) {
 	s := make([]map[string]interface{}, len(opts))