If you are lucky and the wheelbuilder stuck to the rules, you may be able to remove the nipples with a screwdriver stuck into the rim from the tyre side. Nipples have a slot on top, however, if the spoke length is too long, the slot is compromised. If you have "slot" available, it is still a two-man job. One person must prevent the spoke from winding up/twisting whilst the other uses both hands to steady the driver, otherwise the slot can strip too. However, usually the solution is to cut the spoke.