REPLACE

From AgileApps Support Wiki

The REPLACE function searches for a string within a target string. If the search string is found, the replacement string is substituted for the search string.

Syntax
REPLACE('string', 'searchString', 'replacementString',)

Notepad.png

Note:
The searchString is case-sensitive. For a case-insensitive search,
use the LOWER function on both the search string and the string being searched.

Return
Text string
Example
REPLACE('quick', 'ic', 'ar') = 'quark'