REPLACE

Variants:

Pattern-Based Replacing
REPLACE
  [ FIRST OCCURRENCE OF | ALL OCCURRENCES OF ]
  [ SUBSTRING ] old
  IN [ SECTION OFFSET off LENGTH len OF ] text
  WITH new.

Position-Based Replacing
REPLACE SECTION [OFFSET off] [LENGTH len] OF text WITH new.

Pattern-Based Replacing (Obsolete)
REPLACE f WITH g INTO h.