In-car service reminders - do manufacturers set them?

Can car manufacturers force a visit to dealer to reset service reminder? I'm told I need it resetting at a main dealer even though there is the procedure in the owners handbook saying how to do it. The problem is it does not fully reset the warning, it changes the miles but not the months (my car shows miles and month - whichever is soonest).
It can probably be re-set via the OBDII port using the correct diagnostic programme and anyone servicing it properly should have that. Cars are not built for home servicing any more.
Answered by Honest John on

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