Reset Alpha on node

Hey everyone, I hope you’re doing fine.

I don’t seem to find the answer, but I want to put a roto node to isolate a precise shape with a clear alpha after a bunch of compositing and paint work.

Problem is that the node keeps all the previous alpha form the previous nodes.
Is it possible to “reset” the alpha on a specific node ?

Thanks in advance !

Use Swap Channels from the Composite group and set the Alpha to Black.

Works like a charm.
Thanks Marco !