The company president says that significant procedural changes were made before either she or Yeung was told about them.
Conclusion
Assuming what Grimes and the president said is true, the contract was violated.
Evidence
(Assuming the truth of their statements) The contract states that a big change can't be made unless the president or a member of the legal department is told.
Neither the president nor Yeung was told about the big changes.
Evaluate
Okay, so we have a clearly defined goal -- the contract was violated. To reach that verdict, we just have to establish that neither the president nor anyone on the legal team was told about the change in advance.
We already know that president wasn't told in advance.
So we just need to establish that no one on the legal team was told. We know that Yeung was not told, but who cares? We don't know if Yeung is on the legal team, and even if he is, we'd still need to ask the rest of the legal team if any of them were told about the big change.
Goal
We just need an answer to establish that no one on the legal team was told, either.