How to modify/remove Non-editable DNS records

Hi, i have a domain, i want use CNAME to make it point it to my another hosting wiki web, like:
www.mydomain.com CNAME to wiki.mywikihosting.com
But when i name www a CNAME record, DH panel told me that it can't be added since it has a A record in the Non-editable DreamHost DNS records : www A 208.113.148.218

So, my question is : If i have a wiki on another hosting site, how can i point my www.mydomain.com to it?
Is there a way to modify/remove "www A" record?
Thanks very much!

Can you use the other hosting site's DNS instead?

It'd be interesting to hear if customer support would make such a change for you.

Otherwise, you may have to resort to a third party DNS service such as DynDNS.org.

-Scott

Yes, just send a request to support and have them delete your www A record, then you can add the CNAME. I've done this with a couple of my domains.

Thank you all, i'll choose the support request way. :)