"This afternoon when you had come to my residence to inform me about the Parliamentary Board meeting, I had said something about my anguish as also my disappointment over your style of functioning," the BJP veteran said in a letter to party chief Rajnath Singh.
Advani, who stayed away from the Parliamentary Board meeting, told the BJP chief that he decided not to attend the Parliamentary Board as he thought it was "better".
"I had told you that I will think whether I should share my thoughts with other Board members or not. Now, I have decided that it is better that I do not attend today's meeting," he said in the brief letter.
Advani was opposed to Modi as the Prime Ministerial candidate before the forthcoming assembly elections in Madhya Pradesh, Chhattisgarh, Rajasthan and Delhi.
Despite hectic efforts, BJP leaders failed to convince him to back the proposal which has the approval of RSS.