SET CENTURY ON
SET DATE TO MDY
lnMoveMonths = -3 && move forward or backward
lcDelimiter = "-" && SET("Mark") 
lcTextboxValue = "02-2005"
lcTextboxValue = DTOC(GOMONTH(DATE(VAL(SUBSTR(lcTextboxValue, ATC(lcDelimiter, lcTextboxValue) + 1)), VAL(LEFT(lcTextboxValue, ATC(lcDelimiter, lcTextboxValue) -1)), 1), lnMoveMonths))
lcTextboxValue  = LEFT(lcTextboxValue, 2) + "-" +RIGHT(lcTextboxValue, 4)
?lcTextboxValue

>Dear Sir,
>
>I have a character type textbox="02-2005" && February 2005
>I want to substract 3 months from it.
>
>Please elp