Allow invitee to withdraw invite (The invitation has already been withdrawn)

Out of the box it doesn't seem like this module allows the invitee to withdraw/cancel an invite. However, if you are sent an invite you are displayed a status message to either accept or withdraw it which is a bit of a contradiction in code.

When clicking on 'withdraw' from the invitee account I get access denied along with the following status message:
The invitation has already been withdrawn

The invite status is still indeed valid and has not already been withdrawn which is 1 bug. When looking at invite_withdraw_access in invite.module the following code should be changed to remedy this message.

Change
if ($invite->status = INVITE_WITHDRAWN) {

To
if ($invite->status == INVITE_WITHDRAWN) {

To fix the access denied when trying to withdraw an invite from the invitee's account the following change should be made.

Change
if (($invite->uid == $user->uid && user_access($permission)) || user_access('administer invitations')) {

To
if ((($invite->uid == $user->uid || $invite->invitee == $user->uid) && user_access($permission)) || user_access('administer invitations')) {

Patch is attached