Yes, you can upgrade your version of TurboTax and only pay the difference.  Your information will transfer to the Premier version once you upgrade.

How do I upgrade my TurboTax for Windows software?

Upgrading is a one-way street. Once you've upgraded, you can't downgrade back to your original version.

1. With your return open in TurboTax, select Upgrade TurboTax at the very bottom of your screen, towards the right
2. In the new window, select the version you'd like to upgrade to and select Upgrade Now
3. Follow the onscreen instructions to purchase the upgrade
4. When finished, continue working on your return. You don't have to go back to the beginning

https://ttlc.intuit.com/community/upgrading/help/how-do-i-upgrade-my-turbotax-for-windows-software/00/26238

How do I upgrade or switch to a higher version of TurboTax Online?

You can upgrade or switch to a higher version of TurboTax after you've started your 2021 return.

To upgrade your version of TurboTax:

1. Make sure you’re signed into TurboTax and have opened your return.
2. If you don't see this option, select Upgrade from the menu.
   • If you don’t see the menu, select the menu icon from the toolbar.
3. Select the version you'd like to upgrade to.
4. We'll prompt you to pay if you want to print or e-file your taxes. You can also prepay at any time:
   • Select File from the menu. (Don’t worry, you don’t have to file taxes—this just gets you to the payment section.)
   • Select Start or Revisit next to Review your order.
   • You’ll see a summary of your order. Select View payment options.
   • Keep going until you see How would you like to pay for TurboTax? On that screen, select Pay with Credit Card.
   • Enter your credit card information and select Continue.

Once you’ve paid you can go to Tax Home to access your upgraded features.

https://ttlc.intuit.com/community/upgrading/help/how-do-i-upgrade-or-switch-to-a-higher-version-of-turbotax-online/00/26239

I had previously purchased the Deluxe C version and want to update to Premiere version at incremental  cost

@Dale422 the above post gives you instructions on how to upgrade for the Desktop software or for Online.

How do I upgrade my TurboTax for Windows software?

Upgrading is a one-way street. Once you've upgraded, you can't downgrade back to your original version.

1. With your return open in TurboTax, select Upgrade TurboTax at the very bottom of your screen, towards the right
2. In the new window, select the version you'd like to upgrade to and select Upgrade Now
3. Follow the onscreen instructions to purchase the upgrade
4. When finished, continue working on your return. You don't have to go back to the beginning

https://ttlc.intuit.com/community/upgrading/help/how-do-i-upgrade-my-turbotax-for-windows-software/0...

need to upgrade

I'm trying to upgrade to Premier not live

@mork1933   You need to look at the first post in this thread.  It gives instructions on how to upgrade in the  Online version and the Desktop (CD/Download) version.

Yes I would like to upgrade to Premier and have the rental information transferred from DeLuxe to Premier

@Soubisestink 

How do I upgrade my TurboTax for Windows software?

Upgrading is a one-way street. Once you've upgraded, you can't downgrade back to your original version.

1. With your return open in TurboTax, select Upgrade TurboTax at the very bottom of your screen, towards the right
2. In the new window, select the version you'd like to upgrade to and select Upgrade Now
3. Follow the onscreen instructions to purchase the upgrade
4. When finished, continue working on your return. You don't have to go back to the beginning

https://ttlc.intuit.com/community/upgrading/help/how-do-i-upgrade-my-turbotax-for-windows-software/0...

How do I upgrade or switch to a higher version of TurboTax Online?

You can upgrade or switch to a higher version of TurboTax after you've started your 2021 return.

To upgrade your version of TurboTax:

1. Make sure you’re signed into TurboTax and have opened your return.
2. If you don't see this option, select Upgrade from the menu.
   • If you don’t see the menu, select the menu icon from the toolbar.
3. Select the version you'd like to upgrade to.
4. We'll prompt you to pay if you want to print or e-file your taxes. You can also prepay at any time:
   • Select File from the menu. (Don’t worry, you don’t have to file taxes—this just gets you to the payment section.)
   • Select Start or Revisit next to Review your order.
   • You’ll see a summary of your order. Select View payment options.
   • Keep going until you see How would you like to pay for TurboTax? On that screen, select Pay with Credit Card.
   • Enter your credit card information and select Continue.

Once you’ve paid you can go to Tax Home to access your upgraded features.

https://ttlc.intuit.com/community/upgrading/help/how-do-i-upgrade-or-switch-to-a-higher-version-of-t...