If you already filed you need to wait and see if it got Accepted. If it rejects you can fix it and refile. But if it was Accepted you need to wait for the first one to finish processing and you get the first refund or you pay the tax due. Then you can Amend.
Or when you filed did it reject because it said you already filed? Someone else might have claimed your Social Security number ssn by mistake. Then you can only print and mail your tax return and let the IRS sort it out. If your return was rejected you can fix it and try to efile again or print and mail it.