#include <MsgBoxConstants.au3> ; to declare the Constants of MsgBox
Local $sRegex = "(\{.+\"from\":\"(\d+)\".+\"checkId\":\")(\d+)(\".+\"keyword\":\"([a-zA-Z]+)\".+\})"
Local $sString = "{"transfId":"S0722182156164591494745777M","messageId":"123","from":"5777","to":"59395436474","status":-1,"checkId":"1975","price":0,"keyword":"OK","errorCode":601,"errorMessage":"SUCCESS","date":"20150730 09:00:00","model":"wer_tr"}"
Local $sSubst = "$1new Id$4\"checkId\":\"(new ID)\""
Local $sResult = StringRegExpReplace($sString, $sRegex, $sSubst)
MsgBox($MB_SYSTEMMODAL, "Result", $sResult)
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for AutoIt, please visit: https://www.autoitscript.com/autoit3/docs/functions/StringRegExp.htm