Open the 
Source Codes
window.
On the line with the code to be changed, select the code in the Code field.
Enter the new code, and then click Yes. You can also change the contents of the Description field.
You may want to change a source code (such as GENJNL to GNJ).
Open the Source Codes
window.
On the line with the code to be changed, select the code in the Code field.
Enter the new code, and then click Yes. You can also change the contents of the Description field.
All subsequent entries posted from the general journal will have the new source code.