I have a button that is for sending a request for proposal. Once it's sent I want to disable the button so you don't resend the same RFQ to the same suppliers. How would you change or disable a custom action button after it has been used?

The code Im using in the formula that creates the button is as follows:

"<a class='zc-formbutton' href='#Form:Send_Request_for_Proposal?zc_LoadIn=dialog&Request_ID=" + ID + "' >Send RFQ</a>"

How would this be changed to disable the button? Can i add criteria into this code that would disable it? How about making it disappear on records it has been click on already? What about changing the function of the button entirely so it points to a different form?

Anything like this possible and how?

THanks