If it was glued on in the first place I dont see why not. I use a glue from America for all my jewellery projects called E600, which is a flexible strong glue ~ needs to be a flexible glue as the others - non flexible kinds are no good for jewellery. Well clean both parts to be glued to make sure it is grease free, put a little glue on each part to be bonded ~ not too much or it will squish out every where that you don't want glue on when pressed together, wait a minute or two & press together. Leave to set overnight before wearing. Make sure you do not wear for too long in water if possible not at all, though I have a necklace on 24/7 made from using this glue to hold the pieces together & it is always on when I bathe & shower every day, & is fine. Hope this works for you.
Laura . E