A valve device having a valve with first connection elements for mounting the valve in a port of a wellhead, a spool unit having a through-channel, second connection elements arranged in the through-channel, and a flange, the flange configured for sealingly mounting the spool unit to the wellhead, aligning the through-channel with the port, and a plug comprising third connection elements configured for sealingly and removably engaging the second connection elements and attach the plug in the through-channel. A method for removing, replacing or arranging a valve located in a port of a wellhead is also provided.