The role of the EPO in the international phase
For international applications under the PCT, the EPO may act as: 
receiving Office ("RO") (see points 42 ff),
International Searching Authority ("ISA") (see points 190191 ff),
Supplementary International Searching Authority ("SISA") (see points 271272 ff), and
International Preliminary Examining Authority ("IPEA") (see points 291292 ff).
During the international phase of the processing of an international application no designated or elected Office is allowed to process or to examine that application. However, this prohibition may be lifted at the explicit request of the applicant (see points 427428 ff).
WIPO PCT Guide 3.005, 5.005 

Quick Navigation