Regional Jet Technician reported the wrong component was removed for the aircraft and not documented correctly. The aircraft was removed from service and components were correctly identified and replaced as required. Aircraft records were annotated to correctly report the aircraft configuration.

Narrative

Aircraft X over-nighted in ZZZ on Date. The aircraft has a job card to remove cargo smoke detector in the aft position. Name was the technician assigned to this task. We later realized that despite the fact that smoke detector was removed from the inventory software; it was later realized that its still physically installed on the aircraft and it's overdue. The manager regulatory compliance called me and also sent an email with all the paperwork.On the night the aircraft over-nighted Name came to me after the task that he could not do the remove/replace transaction in inventory software. I helped him with the transaction by the information on the job card. I did not physically look at the smoke detector removed to have known that he removed the wrong one. And it was a busy night as usual and could not exactly recalled all that happened apart from just doing the transaction in inventory software. The manager; regulatory compliance; was the one that called to inform me that the smoke detector removed was still physically installed on the aircraft. That the aircraft had to be taken out of service to remove the correct smoke detector since it was already overdue. I told him I will try to remember as much as I can on the event. All I could remember was doing the transaction in inventory software. It is a good practice to physically make sure that the parts have been removed/installed on aircraft and are in the right position.