Below is a script I just put together that will do through each stored procedure in a DB and perform a find/replace (replace @oldvalue with @newvalue). It works by (1) deleting the proc then recreating it with the old value (@oldvalue) replaced by the new value (@newvalue). It works as-is but I highly recommend you add some error handling...

The proc:

CREATE PROC dbo.proc_find_replace

(@oldValue varchar(100),

@newValue varchar(100))

AS

BEGIN

SET NOCOUNT ON;

-- global temp table for storing proc names and DDL definition

IF OBJECT_ID('tempdb..##sprocDef') IS NOT NULL

DROP TABLE ##sprocDef;

CREATE TABLE ##sprocDef (sproc varchar(100), ROUTINE_DEFINITION varchar(max));

DECLARE @sproc varchar(100),

@routine varchar(max),

@execSQL varchar(max),

@n int=1,

@m int=

(SELECT COUNT(*)

FROM INFORMATION_SCHEMA.ROUTINES

WHERE ROUTINE_TYPE = 'PROCEDURE');

-- FOR EACH proc in {yourdb}.INFORMATION_SCHEMA.ROUTINES:

-- (1) drop it

-- (2) recreate it replacing @oldValue with @newValue

WHILE @n<=@m

BEGIN

--colect the name and DDL for each proc in ##sprocDef

DECLARE @sprocDef varchar(1000)=

'INSERT INTO ##sprocDef'+CHAR(13)+

'SELECT TOP 1

SPECIFIC_SCHEMA+''.''+SPECIFIC_NAME AS Sproc,

OBJECT_DEFINITION (OBJECT_ID(SPECIFIC_SCHEMA+''.''+SPECIFIC_NAME)) AS ROUTINE_DEFINITION

FROM INFORMATION_SCHEMA.ROUTINES

WHERE ROUTINE_TYPE = ''PROCEDURE''

AND SPECIFIC_SCHEMA+''.''+SPECIFIC_NAME NOT IN (SELECT sproc FROM ##sprocDef)';

EXEC(@sprocDef);

SELECT@sproc=sproc,

@routine=ROUTINE_DEFINITION

FROM ##sprocDef;

SET @execSQL=

'IF OBJECT_ID(''ajbTest.'+@sproc+''') IS NOT NULL DROP PROC '+@sproc+';'

PRINT 'Executing:'+@execSQL

EXEC(@execSQL);

SET @execSQL=''+@routine+CHAR(13);

SET @execSQL=REPLACE(@execSQL,@oldValue,@newValue);

PRINT 'Executing:'+@execSQL

EXEC(@execSQL);

SET @n=@n+1;

END;

PRINT REPLICATE('-',80)+CHAR(13)+'ALL DONE :)'

DROP TABLE ##sprocDef;

END

GO

Example:

EXEC dbo.proc_find_replace @oldValue='NEHEN_prod', @newValue='NEHEN_test';

Lastly: backup your procs before running this script!