A downhole system and related method, which may be used in an injection well for permitting removal, repair and or replacement of equipment installed in the well without unloading the formation in which the well is placed. The system generally includes an annulus sealing device, such as a packer, at least one valve, such as a flapper valve, a latching assembly and a rigid elongate member. The rigid elongate member may be connected to the latching assembly and serves the valve to open and close, or be permitted to open and close. The latching assembly serves to disconnect, and subsequently reconnect, equipment from the annular sealing device. Such release is accompanied by closure of the at least one valve and reconnection by opening of the at least one valve. The latching assembly has seals to prevent fluid from flowing around the latching assembly when the valve is open.