Update using XQuery

I have the below

First Table

Declare @t1 Table(Id int , PaymentXML XML)

    Insert Into @t1 
    Select 1, '<CreditCard>
            <cc_display_name />
            <cc_type>MasterCard</cc_type>
            <cc_no>************5811</cc_no> 
            <cc_expire_month>4</cc_expire_month>
            <cc_expire_year>2007</cc_expire_year>         
          </CreditCard>' Union All
    Select 2 , '<CreditCard>
            <cc_display_name />
            <cc_type>MasterCard</cc_type>
            <cc_no>****1234567890</cc_no>
            <cc_expire_month>3</cc_expire_month>
            <cc_expire_year>2010</cc_expire_year>        
          </CreditCard>' Union All
    Select 3 , '<CreditCard>
            <cc_display_name />
            <cc_type>MasterCard</cc_type>
            <cc_no>****45678</cc_no>
            <cc_expire_month>10</cc_expire_month>
            <cc_expire_year>2011</cc_expire_year>        
          </CreditCard>' Union All   

    Select 4 , '<CreditCard>
            <cc_display_name />
            <cc_type>MasterCard</cc_type>
            <cc_no>****1234567890</cc_no>
            <cc_expire_month>5</cc_expire_month>
            <cc_expire_year>1997</cc_expire_year>        
          </CreditCard>'
     Select * From @t1 

Second Table

Declare @t2 Table(Id int) 
 Insert Into @t2 Select 1 Union All Select 2 
 Select * From @t2

I need to write an update statement such that for every matching row of @t1 and @t2 table, the PaymentXML column nodes will be updated as under

a) will be blank (i.e. )

b) will be blank (i.e. )

c) will be zero(0) (i.e. 0 )

d) will be zero(0) (i.e. 0 )

I have given a very basic shot but need help as I am new to xquery

DECLARE @cc_type VARCHAR(10)
SELECT @cc_type = ''

Update @t1
SET PaymentXML.modify(
'
    replace value of (/CreditCard/@cc_type.Text())[1] 
    with sql:variable("@cc_type")
')
From @t1 a
Join @t2 b On a.Id = b.Id

Thanks in advance