Across multiple websites, I got conflicting information about reduced relative clauses with the present perfect form. Overall, I came up with the tentative conclusion that relative clauses cannot be reduced for the active voice of present perfect but can be reduced for the passive voice of present perfect.
I would appreciated the definitive answer from grammarians. Thank you!
Active present perfect clauses:
Applicants who have passed the exam go through to the interview.
(wrong?) -> Applicants passing the exam go through to the interview.
The system that has implemented the new software is functioning well.
(wrong?) -> The system implementing the new software is functioning well.
Passive present perfect clauses:
A driver who has been pulled over by the police was 30 mph over the legal limit.
-> A driver pulled over by the police was 30 mph over the legal limit.
The pipe that has been broken will be repaired in a week.
-> The pipe broken will be repaired in a week.
("The broken pipe ..." may sound better, but that's off topic here.)