The principal reason for my change of mind is this.

我改变主意的最重要原因就是这个。

《柯林斯英汉双解大词典》

To explain, I'd like to share my reasons behind this unusual change of mind.

为了解释，我想分享一下我为什么会有这种不寻常的思想变化。

youdao

He had an unaccountable change of mind.

他莫名其妙地改变了主意。

youdao

"In my mind a block of carbon neutral, developing nations could change the outcome of Copenhagen,".

VOA: standard.2009.11.09

You don't have to try to get the change of law You don't have to get the supreme court to change its mind. All you have to do is to get out your credit card and go online and it's done.

不必试图修改法律,也不必游说最高法院,做出什么改变，你需要做的,只是掏出你的信用卡，登陆网站，然后一切搞定。

普林斯顿公开课 - 人性课程节选

All change begins in the mind of single person or a small group."

所有改变从一个人或一小众人的思想开始“

哈佛公开课 - 幸福课课程节选

Why the slight change of mind, given that not having a smartphone has increased my corporate income substantially?

FORBES: After I Dumped My Smartphone - 25% Wealthier But Showing Signs of Weakness

For him, a change of mind on the board's part is quite crucial.

BBC: Usmanov ups the ante at Arsenal

Thus there is time for three more meetings before the American space agency's probe could discover anything that might warrant a change of mind.

ECONOMIST: Forbidden planet | The