The UE sends a Request Bearer Resource Modification (LBI, PTI, EPS Bearer Identity, QoS, TAD, Protocol Configuration Options) message to the MME. If the UE was in ECM-IDLE mode, this NAS message is preceded by the Service Request procedure.
The TAD indicates one requested operation (add, modify, or delete packet filters). In case traffic flows are added, the TAD includes the packet filter(s) (consisting of the packet filter information including packet filter precedence, but without a packet filter identifier) to be added. The UE also sends the QCI requested and GBR, if applicable, for the added traffic flows. The TAD is released when the procedure is completed.
When requesting for a modification of GBR (i.e. decrease or increase), the TAD shall include packet filter identifier(s) for which the GBR change request applies to. The UE includes the GBR requirement of the EPS Bearer. The TAD is released when the procedure is completed.
from 3GPP TS23.401 v850(R8)
5.4.5 UE requested bearer resource modification