Salam
Replacing one aya by another is not about abrogation. There is abrogation of Quran in Quran, but it's situations with situations.
168- سعد عن علي بن محمد الكليني عن إسحاق بن محمد النخعي عن شاهويه بن عبد الله الجلاب قال: كنت رويت عن أبي الحسن العسكري عليه السلام في أبي جعفر ابنه روايات تدل عليه، فلما مضى أبو جعفر قلقت لذلك وبقيت متحيرا لا أتقدم ولا أتأخر، وخفت أن أكتب إليه في ذلك فلا أدري ما يكون. فكتبت إليه أسأله الدعاء وأن يفرج الله تعالى عنا في أسباب من قبل السلطان كنا نغتم بها في غلماننا. فرجع الجواب بالدعـاء ورد الغلمان علينـا،وكتب في آخر الكتاب: أردتَ أن تسـأل عن الخلف بعد مضي أبي جعفر، وقلقت لذلك، فلا تغتم، فإن الله لا يضل قوماًبعد إذ هداهم حتى يبين لهم ما يتقون. صاحبكم بعدي أبو محمد ابني، وعنده ما تحتاجون إليه. يقدم الله ما يشاء ويؤخر ما يشاء: ﴿ما نَنْسَخْ مِنْ آيَةٍ أَوْ نُنْسِها نَأْتِ بِخَيْرٍ مِنْها أَوْ مِثْلِها﴾. قد كتبت بما فيه بيان وقناع لذي عقل يقظان.
H 168 - Saad and Ali bin Muhammad Kulaini have narrated from Ishaq bin Muhammad Nakhai from Shawiya bin Abdullah Jallab that he said: I previously narrated a report from Imam Hadi (a.s) about his son, Abu Ja’far, which proved his Imamate; but when Abu Ja’far passed away from the world, I was so astonished and bewildered that I did not know what to do and I was in a dilemma and I feared writing to the Imam about it. At last, I wrote a letter to the Imam asking him for supplication to Almighty Allah to save us from the hardships imposed on us from the ruler with regard to our youth. Reply to the letter came with a supplication of the Imam and the difficulty of our youth was also solved. At the end of the letter, the Imam had written: You wanted to ask me about the successor after the death of Abu Ja’far (Muhammad) and you are anxious due to that. Don’t be: “It is not (attributable to) Allah that He should lead a people astray after He has guided them; He even makes clear to them what they should guard against.” (9:115)
Your leader after me is Abu Muhammad (Askari), my son. He has everything, which they need. God brings forward whatever He wishes and delays whatever He wishes: Whatever from a Sign We abrogate or cause to be forgotten, We bring one better than it or like it. (2:106) In this is a clear explanation and convincing proof for one who has a watchful disposition.
Kitāb al-Ghayba, Imamate of Imam Hasan Askari (a.s), Hadith #6
Imamate of Imam Hasan Askari (a.s)
thaqalayn.net
This hadith uses it as a proof that Hassan Al-askari (a) will replace Imam Hadi (a).