There's no automated way to move products between stores but it can be done as long as the new store is on the same platform.
The first step is to duplicate each product you want to move from it's more options menu at the bottom of the Product Edit Page:
This will now save the products in your Non-Connected Products section in Dropfied.
Note for Builder Accounts: Once you have duplicated all of the desired products then you can delete your current store in Dropified and then connect your new store (must be in the same platform) to add your duplicated products.
Finally you can send the Non Connected products in bulk to your new store:
Hope this helps.