I found this on how to close a patch with a message:

"To close a patch use a message to that patch name [patchname vis 0("

But I can't make it to work. What could I have missed?

[;
pd-patchname.pd vis 0(

but i don't think that actually closes the patch. just makes it invisible.

to close a patch,

[;
pd-patchname.pd menuclose;(

if you have pd extended, check ../reference/manuals/pd-msg/