Hello, @peanuts-thelilit.

Thanks for reaching out to the Community for support. I'm happy to lend a hand with changing your accountant in QuickBooks Online. 

You can change your accountant by going to the Manage Users section. You'll just follow the same steps as you did when adding them to your account.

Before we start, please make sure that you're logged in as the Master or Company Admin to be able to change your accountant. Let me guide you on how.

1. From the Gear Icon, choose Manage users. 
2. Tap on Accounting firms. 
3. Hit Invite.
4. Enter your new accountant's name and email, then hit Save.  
5. Your accountant will be sent an email with a link to sign in to your QBO company. Then, your accountant will be asked to create a user ID before signing in the first time, unless they already have an account with Intuit Business Services.
6. Once your accountant signs in and accepts the invite, their status will change to Active. 
7. Hit Next. 
8. Click on Finish. 

To remove your old accountant:

1. Go to the Gear icon⚙, then select Manage Users.
2. Find the accountant you want to remove.
3. From the Action▼ dropdown, select Delete.
4. Select Delete to confirm.

For more information about the process, click this article: Invite an accountant to review your accounting in QuickBooks Online. It also contains a video tutorial for visual reference.

Just in case you'll need an additional person to manage your QBO account, you can easily add them as one of the users. Then, to manage what they can and cannot do within your company file, you can restrict their access. 

If you have further questions about removing accountant access in your QBO account, please post a reply below. I'm always around to help. Keep safe