You mean like another W2? That is not a tax return. Was you first tax return filed and Accepted? You have to file all your income on the same tax return.
If your return rejects for something you can fix it and resend it. If it is accepted you will have to amend. So don't change your return until you know.
You should not amend until the first return has fully processed and you get the first refund or your tax due payment has cleared.
How to Amend
https://ttlc.intuit.com/community/amending/help/how-to-amend-change-or-correct-a-return-you-already-...
