Reconnect is “Relink” in Avid-speak. It’s in the Clip menu.
But generally you won’t need to do that. If the media shows offline, you have to make sure that the media is residing in the right folder. Avid is very specific about where media lives.
If the media is OMF (old school), it needs to live in a folder named ‘OMFI MediaFiles’ (sic), and that folder needs to live at the root level of the drive.
If the media is MXF (current formats), it needs to live in Avid MediaFiles/MXF/n , where n can be any number (1 or 2 or 3 or 999), and the ‘Avid MediaFiles’ (sic) should live at the root level of a (media) drive or volume or partition.
If you open Tools->Media Tool, you can see what media is “visible” to the Avid.