url shortener that can be turned off?

I am looking for a relatively well known url shortener that has one or both of the following features:
1) The original person that shortened the URL can turn off the redirection at any time
for example: tinyurl.com/1123 redirects to mysite.com today, but not tomorrow
2) The original person that shortened the URL can change the target URL at any time.
for example: tinyurl.com/1123 redirected to ebay.com today, but tomorrow I turn that off and redirect it to yahoo.com

the url shortener should be relatively well known, it cant be some shady shortener like url-shortening-now.cn

I can see what you're trying to do here and it sure has some possibilities, but I can't think of any major shorteners with the features you seek

geni.us has these features, but it is not free.

can person install adblock?