Android : ShareActionProvider with dynamic Extras changes

I've ShareActionProvider in my application and I can share text which I defined in my Intent Extras in my OnCreateOptionsMenu method:

@Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.share_menu, menu);
        MenuItem item = menu.findItem(R.id.menu_item_share);
        myShareActionProvider = (ShareActionProvider) item.getActionProvider();
        Intent myIntent = new Intent();
        myIntent.setAction(Intent.ACTION_SEND);
        myIntent.putExtra(Intent.EXTRA_TEXT, siteUrl);
        myIntent.setType("text/plain");
        myShareActionProvider.setShareIntent(myIntent);
        return true;
    }

I have a couple AsyncTask's which change my public static siteUrl

How to change the Extras part of the Intent, when AsyncTask is finished ?

I will be grateful for the help.