Filing with a different company.

Once a tax return has been filed it cannot be changed, canceled or retrieved

You will have to wait for the IRS to either Accept or Reject your filed federal tax return.
If the return is rejected you can make the necessary changes and e-file again.
If the return is accepted you will have to amend your original tax return.

Do not amend the tax return until you receive the federal tax refund or the taxes owed and paid have bee processed.

Did you already e-file?

If you e-filed, you have to wait to see if the return gets accepted or rejected.  You cannot get it back.  If the IRS accepts it, you have to just wait for the return to be processed. 

If your return is processed with mistakes or missing information, you can amend after the return has been fully processed.

If yu have not e-filed or if the e-filed return is rejected, then if you decide to "walk away" and prepare your return somewhere else, you can do that.  You will not be amending.  You will just be starting over someplace else.

I wouldn’t use this company again either