وَإِنِ اسْتَغْنَى عَنْ ذَلِكَ لَمْ يَرْكَبْهَا.
Translation: If riding is no longer necessary, he must refrain from riding it.
The earlier clause gives a concession; this one limits it.
Example: riding briefly because of an urgent physical need does not make continued riding permissible once another suitable option becomes available.