LYNN-Using an unmarked vehicle and dressed in plain clothing, police rounded two alleged prostitutes off city streets while on patrol early Wednesday morning.Loretta Thomas, 43, of 376 Washington St., Lynn and Julie Lindner, 23, of 302 Linwood St., Lynn, were both arrested and charged with prostitution in separate incidents.Thomas was arrested shortly after 5 a.m. after she was walking on Lloyd Street near Johnson Street and waved for the male police officer, Patrolman Chris Haggerty, to pull over.Meanwhile, his partner Officer Robert Avery had jumped into the rear compartment of the vehicle to hide himself, according to police.After rounding the block once more, Thomas allegedly waved for Haggerty to pull over near the corner of Lloyd and Whittier streets. She then jumped into the passenger seat and asked him to drive around, police said.According to a police report, Thomas instructed Haggerty to pull over on Bay View Avenue near Hollingsworth Street in the Highlands. Police said Thomas then took out several condoms and allegedly asked Haggerty, “Do you want chocolate or vanilla flavored?”She then said she would have sex with Haggerty in the backseat, charging $20 for oral sex or $30 for intercourse. At that time, Avery popped out from the back of the vehicle and the two identified themselves as police officers.Earlier that morning, around 3 a.m., Haggerty picked up Julie Lindner after she flagged him down on Washington Street near Endicott Street, police said.After Lindner said she needed a ride and got in the vehicle, she stated she was “working” and offered $40 for oral sex, police said.She allegedly asked Haggerty to pull over on Brimblecom Street, where the officers identified themselves and placed her under arrest without incident.