Then, I learned that he only way she could be pulled is to voluntarily step down herself.
That will NEVER happen, so I'm not worried. She's not getting another chance. She knows this.
The DNC can pull the cord any time. They control the ticket.
I was worried myself over the possibility of a switch.
However (and I could be in error here) I think that in
many states the deadline for changing the ballot has
passed, and it is no longer possible to substitute.
Perhaps someone of a more legal technical mind will
clarify this, but I do know that many states do have
a deadline in such matters.