Dreame A2 setup issue: "Robot has already been linked previously"

Hello,

I have this issue on a Dreame A2 of one of my freinds.
I imagine he may have created 2 different Dreame accounts but he doesn't remember with which email / number he created the 1st one on which the robot may be linked.
Is there a way to reset everything and to start a brand new setup?

Msg in French is "Le robot à déjà été lié auparavant"

Thanks for your help