The "EP Pad" Voice is made up of four Elements. Two for the Electric piano and the other two are the String, and the Pad when [AF2 On]
The Assign 1 Knob is set to control the Element Level of the two Pad Elements. Use Assign 1 to set a balance between the EP and the String Pad
Left front panel press the upper Knob Control button repeatedly to select the row "TONE 3"
Use the Assign 1 Knob to set the balance to your liking.
Press [STORE] to store your new version to the USER Bank.