1. Visit the Upgrade site.
2. Log into your registered account. All products need to be on the same email account.
3. Choose the product you wish to upgrade. This means the product that you already own.
4. Choose the product you wish to add. That is the product you wish to upgrade to.
5. Enter your HM2-licensing code (not the product code) in the box and add to cart. All discounted prices will show here.\
See the following screenshot:

If you wish to upgrade from Holdem Small Stakes to Pro Combo, you will need to first upgrade to Holdem Pro, then add Omaha pro.
Holdem and Omaha licenses must match. You cannot use a Pro Holdem and Small Stakes Omaha.