By Echo Wang, Milana Vinn and Matt Tracy NEW YORK, Feb 5 (Reuters) - Elon Musk used a common two-step merger process in SpaceX's purchase of xAI that had the dual benefit of avoiding the repayment of billions of dollars in debt while giving shareholders a tax advantage, according to people familiar with the transaction. It also protects SpaceX from any legal liability from xAI. The deal, announced on Monday, creates a $1.25 trillion company with plans to go public later this year to help ​finance Musk' ...