Hi @marellasunil_3  Hey not sure how you came to conclusion that As "sed command have limitation to use only once" there is no such limitation it would replace multiple occurences of the matched regex if the pattern is same you just have to add global attribute "g" at the end |rex mode=sed field=data "s/Card ((\d+\-)+)/Card XXXX-XXXX-XXXX/g" example  |makeresults |eval data="23/03/2020 13:45:20:123 IST Systemout ..... Card 1234-5678-9012-3456 Card 1234-5678-9012-3456" |rex mode=sed field=data "s/Card ((\d+\-)+)/Card XXXX-XXXX-XXXX/g" Note this would only not work in case the pattern is not matching for the second occcurence  And about your Transforms.conf  [session-anonymizer] REGEX = XXXX ( you have to define the regex which would be the identifier ) FORMAT = $1XXXX$2 ($1 and $2) are the captured named group DEST_KEY = _raw [session-anonymizer] REGEX = (Card) ((\d+\-)+) ( this is the regex) FORMAT = $1XXXX (here there wont be $2 because there is only one group here and your are masking 2nd group so dont include $2 DEST_KEY = _raw if you still have trouble i would share more details with screenshot -------- If you find the answer was helpful, an upvote/karma is appreciated and please accept as solution it would help others as well ... View more