Carolyn Sykes was the captain of the merchant ship Ulysses and for a time was one of Jeffrey Sinclair's on-and-off girlfriends, up to and including 2257.
Carolyn Sykes was a human trader romantically involved with Commander Jeffrey Sinclair in 2257 when he took command of Babylon 5. Unknown to Carolyn through most of their relationship, Jeff was a veteran of the Battle of the Line from the Earth-Minbari War.
Carolyn developed a friendship with Delenn. She stood by Jeff when he was accused of attempting to assassinate Ambassador Kosh of the Vorlon Empire (of which he was thankfully soon exonerated). 
Sometime in the next few months, after trying unsuccessfully to convince Sinclair to quit Earthforce and join her in her the merchant business, the two broke up and went their separate ways. 
Had Sykes stayed throughout Season 1, JMS would have had her get into some sort of trouble with one of the prominent EarthCorps.