If your tax return has been accepted, it is too late to change the direct deposit instructions from savings account to checking account. Do you have both accounts and are the account numbers the same? It's unlikely that the IRS pays any attention to the words savings or checking on your tax return. They will send the direct deposit to the routing number and account shown on your tax form. 

Ok.  I only have a checking account with that bank and that’s my only account number.  It sounds like it doesn’t matter as long as the account number is correct.

Yes if your routing number and account number are correct for your bank account, it doesn't matter that your tax return has savings checked by mistake.