A method and system for performing cell change by a wireless device are disclosed. According to one aspect, the cell change is from a first group of cells of a first radio access technology, RAT, to a second group of cells of a second RAT. Performance of a cell change includes receiving a cell change command. In response to the cell change command, the wireless device synchronizes to interoperate with a first cell of the second group of cells of the second RAT within a first specified period of time. The wireless device synchronizes to interoperate with at least one remaining cell of the second group of cells of the second RAT within a second specified period of time ending after an end of the first specified period of time.