In the current study we plan to evaluate the effects of the conversion from gastric banding to gastric bypass on esophageal function using combined monitoring. The primary aim of the current study is to evaluate esophageal function before and 3-months after the conversion from gastric banding to gastric bypass. A second objective is to evaluate the severity of symptoms, esophageal dysmotilities, endoscopic abnormalities and bolus retention found in patients referred for conversion from gastric banding to gastric bypass. Our hypothesis is that esophageal motility disorders associated with gastric banding are reversed by conversion to gastric bypass.