Replace column substring SQL Server columns

Replace all instances of FINDTHIS with REPLACEWITHTHIS in columns COLUMN1 and COLUMN2 of table TABLE where those substrings are in fact found

update TABLE set
COLUMN1=REPLACE(COLUMN1,’FINDTHIS’,'REPLACEWITHTHIS’),
COLUMN2=REPLACE(COLUMN2,’FINDTHIS’,'REPLACEWITHTHIS’)
from TABLE
where
COLUMN1 like ‘%SUBSTRINGPIECE%’ or COLUMN2 like ‘%SUBSTRINGPIECE%’