I am doing this in Magento 1.9 CE, and my objective is to log out the user as soon as the password is changed. 

1. I registered my extension at `app/etc/modules/Bmg_Golo.xml`:

        <?xml version="1.0" encoding="UTF-8"?>
        <config>
            <modules>
                <Bmg_Golo>local</Bmg_Golo>
                <active>true</active>
            </modules>
        </config>

2. My `config.xml` is at `app/code/local/Bmg/Golo/etc/config.xml`:

        <?xml version="1.0" encoding="UTF-8"?>
    
        <config>
        	<modules>
        		<Bmg_Golo>
        			<version>0.0.1</version>
        		</Bmg_Golo>
        	</modules>
        	<global>
        		<models>
        			<bmg_golo>
        				<class>Bmg_Golo_Model</class>
        			</bmg_golo>
        		</models>
        	</global>
        	<frontend>
        		<events>
        			<controller_action_postdispatch_customer_account_resetpasswordpost> 
        				<observers>
        					<bmg_golo>
        						<class>bmg_golo/observer</class>
        						<method>logout</method>
        					</bmg_golo>
        				</observers>
        			</controller_action_postdispatch_customer_account_resetpasswordpost>
        		</events>
        	</frontend>
        </config>

3. I created an observer at `app/code/local/Bmg/Golo/module/Observer.php`:

        <?php
        /**
        * 
        */
        class Bmg_Golo_Model_Observer
        {
            public function logout($observer) {
                $session = Mage::getSingleton('customer/session');
                    if ($session->isLoggedIn()) {
                        Mage::getSingleton('customer/session')->logout();
                    }
            }
        
        }
        ?>

My customer logged out after changing the password. I doubt the event/observer in config is wrong and my method in the observer is not getting called. Please help me as I am new to Magento.