What is the ruling for forgetting the Tashahhud without forgetting the sitting required for it?

Primary text

If one forgets the Tashahhud but remembers it before completing the sitting required for it, the ruling is the same as if both the Tashahhud and the sitting were forgotten, because the Tashahhud itself is the primary objective. Forgetting obligatory remembrances within pillars, such as glorification (Tasbih) in bowing or prostration, saying 'Rabbi ghfirli' between the two prostrations, or saying 'Rabbana wa lakal hamd', does not permit returning to the place of omission once the position is left, as the place of the remembrance is a valid and integral pillar. Returning would constitute an unlawful addition or repetition of a pillar. However, one proceeds, and prostration of forgetfulness (Sujud as-Sahw) is required for omitting such remembrances, by analogy with omitting the Tashahhud.