How to remove a event listener for a particular key

[Easy-Cloud-in]

Is there a way to remove the event listener for a particular key after it is set for listening to a certain function?

Example:
this.HI.on('tab', function (e) {
if (!CheckTabKey1(e, 'form-content')) {
e.preventDefault();
}

in some other place, I want to reset it and make it look work for another function.

this.HI.on('tab', function (e) {
if (!CheckTabKey2(e, 'contact-form')) {
e.preventDefault();
}

please someone help.