GX-100: Can I use the "EXCHANGE" function in the WRITE menu to swap preset and user memories?

No. The EXCHANGE function on the BOSS GX-100 swaps user memories only. Preset memories cannot be exchanged.

To exchange the positions of two user memories, follow the steps below. Refer to "Saving a memory" in the GX-100 Reference Manual for details.

1. Select the user memory whose position you want to change.
2. Press the [WRITE] button.
   
3. Touch <EXCHANGE> or press the [2] knob.
4. Use the [SELECT] knob or BANK switches and 1-4 switch to specify the user memory you want to exchange the position with and the one you selected in step 1. 
   Select and designate the FROM: and TO: USER PATCHES you want to exchange/swap, this is necessary in order for the <EXEC: [WRITE]> option to be available.
5. Touch <EXEC: [WRITE]> or press the [WRITE] button.
   The confirmation message appears.
6. Touch <OK>.
   * Alternatively, pressing the [4] knob or [WRITE] button can also execute it.