All markers have three types (with the exception of Interior Elevations, which must be a Source Marker); Source, Linked and Unlinked.
Source markers generate content based on model elements. Linked markers reference an already created source content or view. Unlinked markers are a blank slate that reference not model or drafted content or existing view.
A marker may be changed from source to linked, but any source content will either be missing or translated to 2d elements. This is irreversible, and for elevations and sections, new source markers and subsequent views will need to be created. Linked or unlinked markers can not be changed to source markers. Linked markers may be changed to unlinked markers, and unlinked markers may be changed to linked markers.
Moral of the story; do not change source markers/views to linked or unlinked markers. You can create a work sheet from any view if you need to explode view content, or place a new marker if you need the source marker to reference a different drawing.