Issue with user permissions on azure web app (ApplicationPool - Identity)

I am trying to programmatically change the ApplicationPool - Identity property of the IIS server where my azure web app is hosted.

Why am I doing this?

I need to provide X.509 certificate. Implementing this certificate requires some local system data.

What have I done so far?

I use this particular code (pretty much the same from here https://stackoverflow.com/a/9341347/2900305)

private void SetAppPoolIdentity()
{
    string appPoolUser = "myRDP_admin_user";
    string appPoolPass = "my_super_secure_password";

    Action<string> iis7fix = (appPoolName) =>
    {
        bool committed = false;
        while (!committed)
        {
            try
            {
                using (ServerManager sm = new ServerManager())
                {
                    var applicationPool = sm.ApplicationPools[appPoolName];
                    applicationPool.ProcessModel.IdentityType = ProcessModelIdentityType.SpecificUser;
                    //applicationPool.ProcessModel.IdentityType = ProcessModelIdentityType.LocalSystem;
                    applicationPool.ProcessModel.UserName = appPoolUser;
                    applicationPool.ProcessModel.Password = appPoolPass;
                    sm.CommitChanges();
                    committed = true;
                }
            }
            catch (FileLoadException fle)
            {
                Trace.TraceError("Trying again because: " + fle.Message);
            }
        }
    };

    var appPoolNames = new ServerManager().Sites.First().Applications.Select(x => x.ApplicationPoolName).ToList();
    appPoolNames.ForEach(iis7fix);
}

My problem is that my user does not have enough permissions to change the ApplicationPool - Identity to LocalSystem.

And I do not have username and password for specific user (admin or local admin) on azure hosted web app.

Any different approach or idea or workaround are welcomed.

You cannot change the App Pool identity that an Azure Web App runs under. Web Apps execute in a sandboxed environment that generally don't allow this kind of modifications.

There are ways of uploading certificates, and you may want to ask that question specifically if that is what you're trying to achieve.