Selling code rights of use to another author

I have a CodeCanyon JavaScript project that is a jQuery plugin.

Another author has asked if he can buy the rights to use the code of my project in one of his WordPress projects on CodeCanyon.

Am I allowed to sell the rights of use of my code to another author, under the current Envato terms?

Do I need any permission or is it just up to me, as the developer and owner of the code intellectual property?

A few points:

  • I am an Exclusive Author and so is the other party.

  • This would be a private payment. Is this allowed or only payments in the form of Standard and Extended Licenses are permitted?

  • Or should an Extended License be bought and any other further payments made privately?