How to modify the user group of IIS APPPOOL\xxx

I created a IIS website, the application pool name is testAppPool.

Then I run the following code in the website, obtain current user group permissions:

WindowsIdentity winIdentity = WindowsIdentity.GetCurrent();

str += "<br/>Current user name:\t" + winIdentity.Name;   

str += "<br/>Current user authentication type:\t" + winIdentity.AuthenticationType;    

str += "<br/>Current user SID:\t" + winIdentity.User;      

str += "<br/>Current user token:\t" + winIdentity.Token; 

str += "<br/>Token owner SID:\t" + winIdentity.Owner;      

str += $"<br/>Current user has {winIdentity.Groups.Count} group memberships.";      

foreach (IdentityReference group in winIdentity.Groups)   

{        

      NTAccount ntAcc = (NTAccount)group.Translate(typeof(NTAccount));     

      str += $"<br/>&nbsp;&nbsp;&nbsp;&nbsp;Group :&nbsp;&nbsp;{ntAcc.Value}&nbsp;&nbsp;&nbsp; ";  

}  

I got this result like this:

Current user name: IIS APPPOOL\test
Current user authentication type: Negotiate
Current user SID: S-1-5-82-2084461697-3881244625-4442817516-662440669-514472240
Current user token: 2080
Token owner SID: S-1-5-82-2084461697-3881244625-4442817516-662440669-514472240
Current user has 9 group memberships.
    Group :  Everyone    
    Group :  BUILTIN\Users    
    Group :  NT AUTHORITY\SERVICE    
    Group :  CONSOLE LOGON    
    Group :  NT AUTHORITY\Authenticated Users   
    Group :  NT AUTHORITY\This Organization   
    Group :  BUILTIN\IIS_IUSRS    
    Group :  LOCAL    
    Group :  【SID: S-1-5-82-0】

It contains the user group BUILTIN\Users, and I found that IIS APPPOOL\test can access all disks, read and modify.

But I found that IIS APPPOOL\test isn't in the Users Group of Computer Management.

How can I remove the IIS APPPOOL\test account from BUILTIN\Users group.

thanks very much.