Hello Memet

Amelia doesn't have an integration with any membership plugin, so what you're looking for can't be done out-of-the-box.

One of our customers manage to do something similar with Memberpress, and here's his response:

I use memberpress as membership plugin. Memberpress has a addon to link my membership levels to any wordpress user role. So I have linked my levels to the Amelia Customer user role. So each time a member sign up, also assigns the member to Amelia Customer. During the first appointment, all fields are grayed out since Amelia recognizes them as existing customer! This is perfect for me.  You may want to share this technique with others that want similar solution (even with other membership plugin).