Converting While Loop in SP to Set based - sql-server

Question

I am trying to convert a while loop stored procedure to a set-based code .Someone can enlighten me how to do this ? I separate the source data to 2 #temp table based on the #AlertType (email or sms), and inner join the #temptable to based table (itemheader and itemdetail) to replace the code below :
**Old code :**
Where IMD.CustomerAccountNo= #CustAccountNo
AND IMD.StatusCode=#ItemStatus
AND (#Reasoncode = '%' OR IMD.Reasoncode = #Reasoncode)
AND IH.TrackingNo=#TrackingNo
AND IH.ServiceTypeId = #ServiceType
**New code:**
inner join #tempresult_SMS SMS on
IMD.CustomerAccountNo= SMS.CustAccountNo
AND IMD.StatusCode= SMS.ItemStatus
AND (IMD.Reasoncode = SMS.ReasonCode 0R SMS.ReasonCode = '%')
AND IH.TrackingNo=SMS.TrackingNo
AND IH.ServiceTypeId = SMS.ServiceType
But I am struck at the part to generate the #EmailREQNumber in the while loop , how do I generate this number and insert into the table without the while loop ?
#EmailREQNumber + CAST(RANK() OVER (ORDER BY IMD.AutoID ASC) AS VARCHAR)
This is the full SP:
Alter PROCEDURE [dbo].[ezy_UpdateItemHeader](
#SMSNotificationItemDetails ezy_SMSNotificationItemDetailsType READONLY)
AS
BEGIN
SET NOCOUNT ON;
--Declare temp table
DECLARE #SMSDetailTable TABLE
(
[ROWID] INT NOT NULL PRIMARY KEY IDENTITY(1,1),
[CustAccountNo] [NVARCHAR](MAX) NULL,
[ServiceType] [NVARCHAR](MAX) NULL,
[AlertType] [NVARCHAR](MAX) NULL,
[ItemStatus] [NVARCHAR](MAX) NULL,
[TrackingNo] [VARCHAR](MAX) NULL,
[ReasonCode] [VARCHAR](MAX) NULL,
)
--Insert into temp table
INSERT INTO #SMSDetailTable( [CustAccountNo] , [ServiceType] ,[AlertType] ,[ItemStatus] ,[TrackingNo, [ReasonCode] )
SELECT [CustAccountNo] ,[ServiceType] ,[AlertType] ,[ItemStatus] ,[TrackingNo], [ReasonCode] FROM #SMSNotificationItemDetails
DECLARE #TotalRows INT , #CurrentRow INT
SELECT #TotalRows = COUNT(*) FROM #SMSDetailTable
SET #CurrentRow = 0
--Looping start in the first rows
WHILE(#CurrentRow < #TotalRows)
BEGIN
SET #CurrentRow = #CurrentRow + 1
DECLARE #CustAccountNo VARCHAR(50) ,#ServiceType VARCHAR(50) ,#ItemStatus VARCHAR(50) ,
#AlertType VARCHAR(50) , #TrackingNo VARCHAR(50) , #ReasonCode VARCHAR(50)
--Fetch the data into variable
SELECT #CustAccountNo = CustAccountNo , #ServiceType = ServiceType , #ItemStatus = ItemStatus
, #AlertType = AlertType , #TrackingNo = TrackingNo , #ReasonCode = ReasonCode
FROM #SMSDetailTable WHERE ROWID = #CurrentRow
DECLARE #REQNumber VARCHAR(100) , #EmailREQNumber VARCHAR (100)
---Build the transactionID
SET #REQNumber= 'TESTID'+replace(replace(replace(replace(CONVERT(VARCHAR(40),GETDATE(),121),'-',''),':',''),' ',''),'.','')
SET #EmailREQNumber= 'TESTEMAILID'+replace(replace(replace(replace(CONVERT(VARCHAR(40),GETDATE(),121),'-',''),':',''),' ',''),'.','')
--NOtification Item for SMS
IF (#AlertType = 'SMS' OR #AlertType = 'SMS/Email')
BEGIN
declare #NotificationItemDetail table(
[ID] [int],
[TransactionID] VARCHAR(max),
[ItemNumber] VARCHAR(max),
[AlertType] VARCHAR(max)
)
INSERT INTO #NotificationItemDetail (
[ID],
[TransactionID],
[ItemNumber],
[AlertType]
)
Select
IMD.AutoID
,#REQNumber + CAST(RANK() OVER (ORDER BY IMD.AutoID ASC) AS VARCHAR)
,#TrackingNo
,#AlertType
from ItemDetail IMD
INNER JOIN itemheader IH on
IH.TrackingNo = IMD.TrackingNo
WHERE
IMD.CustomerAccountNo= #CustAccountNo
AND IMD.StatusCode=#ItemStatus
AND (#Reasoncode = '%' OR IMD.Reasoncode = #Reasoncode)
AND IH.TrackingNo=#TrackingNo
AND IH.ServiceTypeId = #ServiceType
AND IMD.LastUpdatedDate = CAST(GETDATE() as DATE)
END
--NOtification Item for Email
IF (#AlertType = 'Email')
BEGIN
declare #NotificationItemSMSEMAILDetail table(
[ID] [int],
[ETransactionID] VARCHAR(max),
[EItemNumber] VARCHAR(max),
[EAlertType] VARCHAR(max))
INSERT INTO #NotificationItemSMSEMAILDetail (
[ID],
[ETransactionID],
[EItemNumber],
[EAlertType]
)
Select
IMD.AutoID
,#EmailREQNumber + CAST(RANK() OVER (ORDER BY IMD.AutoID ASC) AS VARCHAR)
,IMD.TrackingNo
,'Email'
from ItemDetail IMD
INNER JOIN Itemheader IH on
IH.TrackingNo = IMD.TrackingNo
where
IMD.CustomerAccountNo= #CustAccountNo
AND IMD.StatusCode=#ItemStatus
AND IH.ServiceTypeId = #ServiceType
AND IMD.LastUpdatedDate = CAST(GETDATE() as DATE)
END
END
END