#include <MsgBoxConstants.au3> ; to declare the Constants of MsgBox
Local $sRegex = "(?m)^([^[]+)\[([^:\]]+)[^\]]*\]([^[]+)\[\/\2\]"
Local $sString = "There's a problem with your [anchor:info]Account Details[/anchor]." & @CRLF & _
"There's a problem with your [anchor:rewards]Sign Up For Rewards[/anchor]." & @CRLF & _
"We didn't recognize this account. Please re-enter your email or [link-to:register]Create An Account[/link-to]."
Local $sSubst = "\1\3"
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