Update or delete splitted data

In customers table I have Email column which could contain multiple emails separated by (;).
I used split function to separate emails for each customer:

Cust1 --->email1
cust1 --->email2
cust1 ---> emailN

And I could add more emails to the same customer.
I want to be able to update or delete the splitted emails, in other words if email2= abc@company.com I want to change it to xyz@company.com or delete it.
Is it possible to do using split function? or any other way?

Here is my split function

CREATE FUNCTION [dbo].[fnSplitString] 
( 
    @string NVARCHAR(MAX), 
    @delimiter CHAR(1) 
) 
RETURNS @output TABLE(splitdata NVARCHAR(MAX) 
) 
BEGIN 
    DECLARE @start INT, @end INT 
    SELECT @start = 1, @end = CHARINDEX(@delimiter, @string) 
    WHILE @start < LEN(@string) + 1 BEGIN 
        IF @end = 0  
            SET @end = LEN(@string) + 1

        INSERT INTO @output (splitdata)  
        VALUES(SUBSTRING(@string, @start, @end - @start)) 
        SET @start = @end + 1 
        SET @end = CHARINDEX(@delimiter, @string, @start)

    END 
    RETURN 
END

Calling the function to split emails:

select tb1.custId, split.splitdata from customers tb1
outer apply [dbo].[fnSplitString] (tb1.email,';') split
where tb1.Email like '%;%'

To add new email to the same customer:

UPDATE Customers set Email=Email+';new Email' Where CustId='customerId'

for updating or deleting existing emails, any suggestions?

Thanks in advance

via Chebli Mohamed