If you have a concern, your should be to try and take care of it at the lowest level possible! That means having a conversation where you raise your concern. You can bring anyone with you (including your site rep, or someone from Grievance or Exec Board) with you for this conversation. The conversation should be summarized in a follow up email sent to all parties. In the rare case that this isn’t possible, someone else can have this conversation on your behalf, allowing you to be anonymous. If you are unable to resolve things at this informal level, then your next step depends on the concern.
Grievance: A grievance is used when it is believed that the contract has not been honored.