One of the ways of migrating content (Avaz backup) from your existing app to the new app is via iTunes by connecting the iPad to MacBook or Windows. to the computer via a suitable cable.
For MacBook users
A) Transfer backup from source iPad to MacBook
1. Connect the iPad to your MacBook using a suitable cable.
2. Open the Finder.
3. Tap on your iPad that shows up on the Left side bar.
4. Tap on Files on the top Menu.
5. You will see the list of backups under Avaz folder. Select the backup that you want to transfer.
6. Move this backup to the combined app.
7. This backup will reflect in the new app and will be found under Menu > Settings > Backup & Restore > List of Backups.
8. Tap on the backup and select Replace to replace the existing vocabulary in the combined app.