How to change the arc base

Question

Pretty new to arcanist. Using it for the first time. Apology if the title does not make sense with the content of the question.

I have one branch named: dev-branch-for-project. This is upstream branch for all other branches in my project.

I created two branches out of this branch and was working on both of them parallelly:

Branch1:

• arc feature create-skelton-for-project
• Made the changes
• Raised a diff with arc diff

Branch2:

• arc feature add-functionality-to-skelton
• Made the changes
• Raised the diff with arc diff

As you can see, I was working on both the branches parallel and raised the diffs for review on both of them. Both of them were getting reviewed.

Branch1 create-skelton-for-project got approved and I landed this branch with arc land. Changes of this branch got merged in dev-branch-for-project

Now I did the following on branch2:

• git checkout add-functionality-to-skelton
• git rebase -i dev-branch-for-project
• arc diff

The issue I am facing is, now diff which is under review for branch2 in showing the changes which belong to branch create-skelton-for-project and are merged already in dev-branch-for-project.

• What did I miss?
• I should not have done the rebase when the diff is under review? What's the recommended process for rebasing the current branch?
• How can it be fixed? The Person reviewing the diff for branch2 is now seeing changes from branch1 and branch2 both in diff2