The Record Action switch selects how the RC-505 will behave when you're recording your loops. When you press one of the Track buttons to begin recording, and then press the button again, it will either switch to Overdub Mode, or to Play Mode- depending on the setting of the Record Action switch.
Here's how to set it;
1. Choose a Memory location to edit.
2. Press the MEMORY button.
3. Press the parameter right (>) button to select "REC: Rec Action."
4. Turn the MEMORY/VALUE knob to select the desired setting (REC >OVERDUB, REC >PLAY).
5. Press WRITE twice to save the new settings to the Memory location.
Note: This is not a global setting and will need to be repeated for each memory location.