The formalities officer will, at any stage in the procedure, immediately communicate the observations of any of the parties to the other parties for information.

If the proprietor of the patent files amended documents with his observations, where applicable as part of an alternative request, the formalities officer will invite the other parties to submit observations within a period to be fixed by him (normally four months).

If the Opposition Division considers that observations are called for in the course of the further procedure, a separate invitation is issued and a period is fixed (normally four months), with or without a communication stating the grounds.