The first phrase that came to my mind was "to let of".
Letting go of his pendant, Tom got up from the bed and stood in front of me.
I'm not sure, though, if "letting go of" is an ambiguous phrase. I'm looking for a word/phrase that means to "unhold" and that can't be mistaken with "letting fall". So in the example, Tom isn't letting the pendant fall onto the floor, but just letting it go back to its original hanging position.