Dear Silke
To close the GOS affiliation you don't need to add the GOS entry again. You should just add the status "closed" to the existing affiliation.
To do so click on the "edit" icon by the GOS affiliation and on the "add status" button (see attachment).
If the whole station is closed do not forget to fill out the "date closed" field at the top of the station form.
I hope it helps
Lucia
