Substituting exercises
The Workout Builder has incredible customizability when it comes to modifying a program. One such method is by substituting exercises. You may want to swap an exercise in the Workout Builder with another to accommodate the equipment you have or don't have access to, injury, or even just personal preference.
Accessory Lifts
On any accessory lift exercise, tap/click the ⌵ icon to open the menu of available substitutions as shown:
Every exercise will have different substitutions. In the case of this Romanian Deadlift, there are so many alternatives, it can't even be displayed on a single screen:
Main Lifts
Main lifts can also be changed, but it is done by modifying the workout, not just swapping the exercise.
The following information is also available in the article Changing Your Program Settings.
Start by tapping/clicking the Options icon in a workout:
That will bring up the following panel. Tap/click Edit Workout.
That will bring up the following settings panel:
Scroll down, you'll see the Main Lifts selection, where you can make changes: