how do I reheat a pan of lasagne?

Anytime I've had to reheat a full pan of lasagna, I've done it with a water bath and it turns out great!

I reheat individual serves either in the microwave or the oven. I think they are less likely to dry out and reheat more evenly.

Or, if the microwave is big enough you could warm it in there and then finish with a few minutes in the oven (maybe 7-10 min at 350 or so)

I would cover it with foil and place in a preheated slow oven (that is, about 250º till heated through, perhaps about 20 minutes or so (For a regular family dinner I'd just microwave individual portions). Maybe others will add their $.02