Yes, you can. To change the sound of layer A press the MISC PARAMS button. Turn the parameter knob to scroll to the menu item named "Layer A: B## P##" where you can audition layers. Then use the bank and program knobs to scroll through the presets.
Similarly, to change the sound of layer B press the MISC PARAMS button and navigate to "Layer A: B## P##." Then press the Edit Layer B button to enable auditioning for layer B sounds. Use the bank and program knobs to scroll through the presets again. If you wanna return to layer A, simply click on Edit Layer B button again.