If you are using firmware that enables quick connection after power loss, low power consumption is achieved by powering off the Wi-Fi module. Therefore, simply powering on the Wi-Fi module will wake it up.
If you are using firmware that allows the module to enter low power mode via pin operation, you need to pull the pin high to wake it up.
If you are referring to the module reporting a network status of 5, simply sending a reset command will allow the module to re-enter network configuration mode.