Update state of the Ribbon Control

Control could be in the Enabled or Disabled state. Disabled control is visible, but it doesn't respond to the user actions. Usually it looks muted. 
With Application.Ribbon.Tabs(TAB_ACCOUNTS)
.Controls(BTN_REG_PAYMENTS_NEW).Enabled = true
End With
This example of code enables button New Regular Payment on the Accounts tab.
Custom Ribbon
You can use Visible property to hide control. When you turn OFF visibility, control disappears from the Ribbon.