You can change your purchased package at any time in your Meet5 app. 

Tap on "Profile" at the bottom right and then on "My Club / Premium".

There you will find all the information about your package. Tap on "Change package" to view all packages and their functions. There you can choose the package of your choice. The App Store will automatically deduct the amount you have already paid. The amount you have already paid will not be lost!