I filed singe instead of mfs should i amend to mfs

Yes. You should amend your return as this will impact the amount of a refund you receive. You can amend using TurboTax. Follow these steps:

Before you get started, read this to make sure you actually need to amend.

1. Sign in to your TurboTax account, if you're not already signed in. 
2. In the 2016 Tax Year section, click Amend (change) return. 
   • Note: If you see an orange Take me to my return button, you can't amend because you haven't filed yet. Just click or tap that button to open your return and make your changes.
3. In the pop-up, click Amend using TurboTax Online
4. Click Continue on the We'll help you change (amend) your return screen.
5. Follow the on-screen directions to amend your return.
   • Don't worry if your refund drops to zero or does strange things while you are amending. Your calculations will come out correctly in the end.
6. When you're done, we'll provide instructions to print and mail your amended return because an amended return can't be e-filed.

You can track your amended taxes with the IRS tracking tool. It takes the IRS around 16 weeks to process your amended taxes.

The processing time for amended state return differs from state to state. Contact your state to find out how long it takes them to process your amended taxes.