Yes, you can!
Lydia lets you pay anybody even without any network available. Just tap the amount and choose a professionnal to pay him with the QR Code. If you want to pay a friend, tap “a contact” and tap on the QR Code symbol at the top right of the screen.
In both cases, the recipient will be able to scan the QR Code on your screen with his own app. He will need to have an internet connection to do so.