Is it Possible to change sponsor after getting listed?

[caringneo]

Hi,
I had a free site listed few months back and later I found that the sponsor is no more alive. I just left it as it is. Now last week, I got a site listed with DD, GG , Cleo and others and have been getting more than 1000 hits a day. But my sponsor click throughs are less than 50. When I contacted my webmaster friends, they all had cautioned me against the particular sponsor I used.

Now is it ok, to just change the sponsor with out changing anything else?
I remeber Cleo had said once that, it is ok, as long as you don't touch the content. How about others? Because if you are using script to check the sites (like TGps), then there are chances that, I will get blacklisted for changing the HTML aslo, since the scripts don't see the site like human eyes.
I don't intent to change anything unless its perfectly ok for you. Waiting for your opinions.
Neo