Your registrar would be the best one to give you guidance on this… especially with the new ISO 9K2K standard being out.
My expectation based on previous experience with ISO 9K is that you’ll have to go through the whole registration process, as you did when you were first registered (same amount of man-days etc), then they’ll repeat their current surveillance process & frequency. Given how AIAG has not spoken regarding ISO 9K2K I susupect that your registrar may register you to the current QS standard (which only has the ISO 1994 version) with the caveat that they’ll upgrade you to the ISO 9K2K whenever AIAG decides what they want to do.
Please let us know what your registrar’s final decision is… my current company is QS registered and we’re waiting with baited breath to see what AIAG will decree on this topic…