Hello, @nitish-singh, @gurikbal-singh, @peterjones and All,
As some of the lines of the XML file are, likely, preceded by some leading blank characters, the solution, below, should be preferred :
SEARCH ^\h*<isRetrievable>false</isRetrievable>\R\h*<idName></idName>\R\K\h*<readOnly>true</readOnly>\R?
REPLACE Leave EMPTY
Best regards,
guy038