Yes, you should have the ability to remove old accountants and invite new one if you’re logged in as the Master or Company Admin.
We currently have an open investigation taking place about some users not being able to add accounting firms in QuickBooks Online. Our product team knows and is working to get a permanent fix as early as possible.
I recommend giving our Customer Care Support a call to include your account to the list of affected users. This way, we’ll be able to notify you of any updates available.