You can use the preapply exit to modify a before-image or after-image
that is applied to a VSAM data set.
When the Exit Is Called
The preapply exit is called before CICS VR updates a VSAM data set with either
the before-image, for backout, or the after-image, for forward recovery, for
data sets that are being recovered in this CICS VR run.
Parameter List
The parameter list that is passed to the preapply exit.