How can I transfer playlists and favorites from one account to another on the same platform?

Even if it's impossible to connect multiple accounts of the same service at the same time on Soundiiz, there's a workaround to transfer your data between them. 

Using Soundiiz as a destination

1. Connect your first account to Soundiiz
2. Transfer all your data to "Soundiiz" as a destination
3. Disconnect your first account and connect the second account
4. Transfer all your data from "Soundiiz" to this new account as a destination

Using CSV Files

1. Connect your first account to Soundiiz
2. Export all your data as a CSV file
3. Disconnect your first account and connect the second account
4. Import all your CSV to this new account

You will be able to copy your playlists but also your favorite tracks, artists, and albums (if supported) between two accounts on the same service.