I don't believe the difference between rework and repair has anything to do with pre-market or post-market. It has to do with the state of the resulting product, whether it meets all original product requirements, or enough of them to be acceptable for use.
We can twist and turn the words 'Rework' and Repair' from the english point of view, however we are talking about control of non conforming product = control of non conforming medical device servicing, which is a possible outcome from a servicing effort.
If we are talking about application of ISO13485 to medical device servicing scope, the above needs to be addressed and handled per the requirement of clause 8.3. Details and authorization about handling NC servicing situations needs to be flown down from the manufacturer to the servicing company.
The moment you are called in for servicing, you are dealing with a NC product, which is an input.
What ever and all that you perform is the servicing activity (your product per scope) and the output is expected to be a conforming product. If not, your servicing activity (your product per scope) may be non conforming, or the product is beyond your servicing ability. You need to address these situations in the QMS as the standard details.
a) by taking action to eliminate the detected nonconformity; = re-visit / re-service (rework, repair, whatever)
b) by authorizing its use, release or acceptance under concession; = (If trained and authorized to do from the original manufacturer)
c) by taking action to preclude its original intended use or application. = de-commission and return to manufacturer or other action that you are trained to do.
We need to go by the business sense and requirement and map activities to the standard's requirement.