Reassure your child, give her comfort. Talk to her about the move, and give her attention, both you and your spouse, to reinforce her security from the love of her parents. Talk up her self-esteem. Ask her gently, discuss with her, if she wants to go to pull-ups, or even nappies - she may well be upset over these accidents. If it's just imposed, you may find you're adding another trauma, that'll have repercussions further down the line.