iRule modifies the cookie to include the domain name

Hi , I am new to irules and I have a question and hope someone help me. I need to add a domain name to a certain cookie (modify the cookie to include the domain name also) and an irule to do the same for the all cookies.

I have did this for all the cookies (I don't know if its a valid one) rule Add_Domain_To_Cookie {

when HTTP_RESPONSE { set newdomain "abcdef.com" foreach mycookie [HTTP::cookie names] { HTTP::cookie domain $mycookie $newdomain } } }