Is it possible if (After getting EIN) I change my LLC type
(disregarded entity or C type or S type or corporation or change in
number of members) for tax saving ?
You marked your question as "real-estate", so I'm guessing you're holding rental properties in your LLC.
That means that you will not be able to qualify for S-Corp, only C-Corp treatment. That in turn means that you'll be subject to double taxation and corporate tax rate. I fail to see what tax savings you're expecting in this situation.
But yes, you can do it, if you so wish. I suggest you talk to a licensed tax adviser (EA/CPA licensed in your State) before you make any changes, because it will be nearly impossible to reverse the check-the-box election once made (for at least 5 years).