Reversible data modifications within DS units

A computer readable memory comprises:

• a first memory element that stores operational instructions that, when executed by a computing device of a dispersed storage network (DSN), cause the computing device to:
• send a set of destructive modification requests to a set of storage units of the DSN regarding a set of encoded data slices, wherein a data segment of a data object is dispersed storage error encoded to produce the set of encoded data slices, wherein a decode threshold number of encoded data slices of the set of encoded data slices is needed to recover the data segment;
• and
• a second memory element that stores operational instructions that, when executed by the set of storage units, cause the set of storage units to:
• determine, by each storage unit of a decode threshold number of storage units of the set of storage units, whether to preserve a respective corresponding one of the decode threshold number of encoded data slices prior to executing a corresponding one of the set of destructive modification requests;
• when determined to preserve the respective corresponding one of the decode threshold number of encoded data slices prior to executing the corresponding one of the set of destructive modification requests, determine, by a first storage unit of the decode threshold number of storage units, to flag a first encoded data slice of the decode threshold number of encoded data slices or temporarily store a copy of the first encoded data slice, wherein the first encoded data slice is the respective corresponding one of the decode threshold number of encoded data slices of the first storage unit;
• and
• when determined to flag the first encoded data slice, flag, by the first storage unit, the first encoded data slice as preserved.