Long-term complications after sleeve gastrectomy (SG) requiring revisional surgery include predominantly inadequate weight loss, recurrent weight gain, worsening of a significant obesity complication, and intractable gastroesophageal reflux disease (GERD), including Barrett’s esophagus. Revisional surgeries in the form of re-sleeve or banded-sleeve and conversional surgery in gastric bypass (Roux-en-Y gastric bypass [RYGB], one anastomosis gastric bypass [OAGB], biliopancreatic diversion with duodenal switch [BPD/DS], and single anastomosis duodeno-ileostomy with sleeve gastrectomy [SADI-S]) are described. OAGB seems to be a safe and effective second-stage rescue procedure after SG. OAGB links the anti-reflux effects of RYGB as a low-pressure system and a less dangerous malabsorptive procedure than BPD/DS. The results of conversions of SG to RYGB and OAGB during 2014–2024 in our centers have shown the differences. The best anti-reflux procedure is the RYGB, and more efficient weight loss can be achieved after OAGB. The length of the biliopancreatic limb plays a key role in both procedures.