What is the rule of the law of our circuit on a motion to amend or amend a habeas petition?

We adopted the rule just mentioned as the law of our circuit in Woods v. Carey , 525 F.3d 886 (9th Cir. 2008). There, a pro se petitioner filed his first habeas petition in the district court. Before that petition had been finally adjudicated, he filed a second petition in the same court. The district court dismissed the second petition on the ground that it was second or successive under 2244(b)(3) and that the petitioner needed, but had not obtained, our court's authorization to file it. We held that the district court erred by regarding the new petition as second or successive because, at the time the new petition was filed, the first petition remained pending and had not been finally adjudicated. Id. at 88890. We further held that, because the petitioner was proceeding pro se , the district court was required to construe the new petition as a motion to amend the first petition. Id. at 890. We vacated the district court's order dismissing the new petition and remanded for the court to exercise its discretion in deciding whether to permit amendment under Federal Rule of Civil Procedure 15. (The petitioner had already amended his first petition once, so he was not entitled to amend it again as a matter of right. Id. at 890 n.3.)