When viewing a file with a nonlinear regression result, to view the details of that equation:

1.Go to the Model tab of nonlinear regression

2.If you use Windows, on the right side of the dialog, click the "Edit..." button.
If you use Mac, on the right side of the dialog, click the button with the gear icon.

3.You'll see the Equation dialog that lets you see the equation, the rules for initial values, the default rules for constraints, and the list of transforms to report. If this is a user-defined equation, you can change anything you want. If it is a built-in equation, you can't change anything. If you want to change a built-in equation, you need to "clone" it. and then edit the copy.