We have 34 members in a workspace on Trello Premium licenses. I want to change our licensing plan to Standard. How do I do this? I followed the support article that said to navigate to Workspace settings, billings, explore plans and then select the appropriate plan. However, there is no option/button for me to select 'Standard'. We pay annually and the next billing is due on 21 July but we have new members being signed up along the way.