Methods, systems, and devices for wireless communications are described. A user equipment (UE) may retune from a first narrowband carrier to a second narrowband carrier. The UE may determine to retune in one or more symbols of either a first narrowband subframe or a second narrowband subframe based on the number of symbols for the UE to retune and a number of other factors. The other factors may include the start symbol of a downlink channel scheduled in the second narrowband subframe, the number of antenna ports configured for the UE, hybrid automatic repeat request (HARQ) identifier (ID), coding rate or effective coding rate, among others. The UE may determine to retune in the first narrowband subframe, the second narrowband subframe, or in both subframes in order to utilize reference signals transmitted to the UE and reception of all downlink messages scheduled for the UE.