The World Federation One Stop Fiqh

Ruling 977

If a person forgets a part of the other surah or is unable to complete it due to some compelling reason, such as shortness of time, he can leave that ]surah and recite another ]surah instead even if he has reached half of it and even if the ]surah he is reciting is al-Ikhlāṣ or al-Kāfirūn. In the case of forgetfulness, he can suffice with the amount he has recited [and he does not need to recite another full ]surah].