Embodiments of the present application relate to a method and apparatus for multicast and broadcast services (MBS). An exemplary method includes: determining an association identity (ID) for associating a common layer entity with a first lower layer entity for a multicast data radio bearer (M-DRB) and a second lower layer entity for a unicast data radio bearer (U-DRB); and transmitting configuration information including the association ID. Embodiments of the present application can support dynamic change between the point to multipoint (PTM) mode mode and the point to point (PTP) mode mode while providing lossless and seamless transitions and/or handover between the PTM mode and the PTP mode.