check if a mac adress is in use

Hi,

 

Ive got the following question. maybe you guys know it but i still have to ask.

I am working with broadworks. When i add a device i olso have to add a mac adress.

Is there a way ( a request or something) i could use so i a list of every mac adress that is in use in broadworks and/or a list that contains all mac adresses in use. I need to know this because when i update a device . i first need to delete it and than add a new one because there isn't a request to update it. hoewver the first part goes well ( the deleting) however whenever i try to add a mac adress that is already in use it can't be added. So i need to do a check that for the device i want to change the mac adress that i added isn't in use.