Change the Owner of SQL Reporting Services Subscription

Question

So, I am having this odd issue after our Sysadmin changed my user name from what it used to be to something new.
Now, subscriptions for reports that I had created for users are not working anymore. And it gives me following error,
Failure sending mail: The user or group name 'DOMAIN\MyUser' is not recognized.Mail will not be resent.
A quick Google, landed me on
this old tip from MSDN about changing owner of report. According to that tip all I have to do is to update all entries in  "subscriptions"  table from older user to new user id, but for that new user should exist in "users"
table  but in my case it didn't exist. So as suggested in very bottom of that same tip, I created (and deleted) bunch of items using Report Server Manager. But it didn't create my new user.
Then, I removed old subscription and created new subscription. But it still shows my old username as owner of that subscription.
So my question is, how do I change Owner of Subscription ?
UPDATE:
I forgot to mention that I am using SQL Server 2008 SP3
TIA,
Jack

Answer 1

ListSubscriptions only takes one argument...
http://technet.microsoft.com/en-us/library/reportservice2010.reportingservice2010.listsubscriptions.aspx
If i grab the first 4 lines of that script then write the subscriptions variable to screen i can see all my subscriptions in our system.
As mentioned the script is meant to get you started.  It could be failing on the authentication.  So depending on how your system is configured you might need to do something different in how you connect.  You'll probably have to do a little
research to get everything to match up with your environment and configuration.
I am not sure if it has something to do or not ... but I am using SQL Server 2008 SP3. And so if I use code like below,
$ssrsProxy = New-WebServiceProxy -Uri "http://<report server>/reportserver/reportservice2005.asmx" -UseDefaultCredential
$ssrsProxy | Get-Member
Then I can see that ListSubscriptions has following definition, and it shows that it is actually expecting 2 arguments.
ListSubscriptions                            Method     Microsoft.PowerShell.Commands.NewWebserviceProxy.AutogeneratedTypes.reportservice2005_asmx.Subscription[] ListSubscriptions(string Report, string Owner)
May be it is because I am using SQL Server 2008 ... not sure.