Paid for TurboTax, but found a double entry that changes the fed and state refund. How do I adjust the amounts to receive the proper credit?

Have you already e-filed your return?  If so, you will need to wait until the IRS either accepts or rejects your return.  If accepted, you only have the option of amending your return to correct the double entry.  How do I amend my 2019 TurboTax Online return? - Community

If rejected, you can re-visit your return to correct the information.  How do I fix a rejected return? - Community

Because I am unsure of the exact location of your mistake, I will provide general instructions for how you can revisit a section to make corrections (if you have not already e-filed). 

1. Log into your TurboTax Online account.
2. Select Search at the top of the page.
3. Type in the form or section where you made the error (i.e. 1099 misc)
4. Select the Jump To link that populates in the search results

From here you should be able to navigate through to the location where you made the error.