I'm not an electrician, but I'm pretty sure that that definitely wouldn't be allowed by the NEC.

You'd probably need something that switched both the hot and the neutral, like a Double-Throw Safety Switch (see link below).

Or you could install two receptacles (on different circuits) side-by-side at the washer and just unplug it from one and plug it into the other.

Either way, it seems like it would be a pain in the butt and you would frequently forget to switch it over to the proper side.

Here is a link that might be useful: Double Throw

You can't do it primarily because the neutral needs to follow the hots in the circuit. Since you say "submetering" you mean that you intend to keep with one service but want to bill your tenant for their use.

Frankly I can't imagine that it would be cost effective nor practical to have some kind of switch. Up the rent by a few dollars per months to cover the cost of utilities and be done with it. Or install a washer/dryer with a coin slot.

This is a common transfer switch application isn't it?