Sure, should be reusable. If you’re really concerned about traces of energy, use some method to clear it. If you don’t think you can do this with your intent alone, try asking your servitor to help you out, or you could also try using one of the Intercession audios and ask them for help. Really shouldn’t need to tho I wouldn’t think.
Servitor probably could do this, yeah. Try it out by asking them, then let us know how it works out! Alternatively, you could use the lucky sigil to charge the new item without changing the old - there’s no limit on the number of items you can charge, except the time it takes to do so.