Riker made her last appearance on September 21, 2016.
She returned on December 22, 2016.
On June 11, 2021, it was revealed that GH plans to recast the role of Naomi and bring the character back.
On August 6, 2021, Naomi was recast with the actress Gigi Bermingham. Her character was killed off on August 10th.
Naomi Dreyfus is the ex-wife of Raymond Berlin, who organized a ponzi scheme on Wall Street a few years ago and is responsible for swindling people out of millions. She is also the mother of Hayden Barnes (birth name Rachel Berlin), through an affair with Dr. Jeff Webber.
Naomi also continues to insist that she had nothing to do with what her husband did. Raymond is currently serving over 200 years in prison for multiple counts of security fraud.
On June 3, Naomi arrived at Wyndemere, much to Hayden's surprise. On June 4, it is revealed that Hayden and Naomi are estranged because Hayden is mad at her for turning her father into the Feds. Naomi stands by her decision, and offers to help Hayden get the Feds off her back. She also wants her white diamond necklace back. The white diamonds are in Hayden's possession and one was sold by Hayden's husband Nikolas Cassadine.
Hayden says she doesn't have it because Nikolas has them, and they are gone with him. Naomi says Hayden is lying, and says she is just as greedy as her father. Hayden snaps that between her and Elizabeth Webber, she has had enough. Hayden picks up on Naomi's reaction, and asks if she knows Elizabeth. Naomi says she sounds familiar, and Hayden decided to just leave the issue alone for now. Naomi suggests she and Hayden search for the white diamonds tomorrow. It was eventually revealed that Naomi had an affair with Jeff Webber and they conceived Hayden, making Elizabeth Webber, Hayden's half-sister.
In September 2016, Naomi confessed to stealing diamonds that belonged to Raymond to protect Hayden, who actually stole them. The Feds took back the diamonds. Naomi was arrested and then released a couple months later before leaving town in December 2016.
On July 29, 2021, Sam tells Nikolas she is looking for Naomi as Hayden has been missing for over a year.
On August 6, Naomi visits Finn and Violet. Naomi tells Finn she is staying at the Woodbridge Motel. Her affair in Europe has ended and she is back in town. Finn asks her about Hayden and she claims to not know and makes plans to have tea with Violet.
On August 9, Sam and Shawn go to the motel to ask Naomi about Hayden's disappearance, but Naomi tells them that she has no relationship with her daughter whom she referred to as Rachel Abigail Berlin. After Sam and Shawn left, Naomi told an unknown man that she told them nothing about Hayden. However, as the two figure out that Hayden's real middle name is Samara, Naomi is murdered by the unknown man via overdose.
On November 4, Shawn accuses Nikolas of killing Naomi. Nikolas denies it and when Shawn leaves, Nikolas calls Victor Cassadine and asks him if he killed Naomi.
Adultery; had an affair with Jeff Webber while they both were married 
Drug trafficker [revealed Jul 17, 2016]
Confessed to stealing a diamond necklace intended for auction by the Feds [Sep 21, 2016]
Collapsed due to a panic attack and had to go to the hospital as a result [Jul 21, 2016]
Confessed to stealing diamonds that belonged to Raymond to protect her daughter, who was the one who actually stole them [Sep 2016; arrested and then released a couple months later]
Died after either Victor Cassadine or someone working for Victor had injected her in the neck; framed as a medication overdose [Aug 9, 2021; revealed on Aug 10, 2021; injection revealed on Aug 13, 2021; Victor's involvement revealed on Dec 6, 2021]
↑http://soaps.sheknows.com/general-hospital/comings-and-goings ... "Robin Riker, who first appeared on "General Hospital" as Hayden's mother, Naomi Dreyfus, on Friday June 3 has left the show. Though The Feds took Naomi away after she visited Hayden in jail, it's possible that she could make another Port Charles appearance in the future."