Hi there,
It may be too late, but here it is:
1. Duplicate your sequence.
2. Open the duplicate (daughter sequence) and delete the media content (except the markers, because this is what you need)
3. Export/import a short clip with the settings you need for the daughter sequence OR import an existing clip with the required settings
4. Drag the clip into the timeline and select ‘Change sequence settings’ from the pop-up message ‘Clip Mismatch Warning’.
5. The daughter sequence has the markers from the parent
6. Copy/paste the content from the parent OR just drag the parent sequence to the daughter timeline – I’d use the second option, since in my case, I need to scale down the media from HD to SD, and I can do it at once, not clip by clip.
Hope this helps,
Mark