Marisa used to do this too, not so much now, but I think it's a way that they deal with their emotions at this age, especially with another sibling in the picture. Make sure you have plenty of one on one time with her, just do some mummy/daughter things regularly and I find alot of Marisa's less positive behaviours reduce when I do this. Also she thrives when she gets time away from Elijah. She loves him to bits, but she is in her element when she gets to stay at nanna's house and do lots of fun things, without the interruption of a little brother

Never underestimate having a conversation about it with them too. I would always ask Marisa, 'Why do you wee in your pants sweety? Why don't you use the toilet like big girls?' The more level-headed I deal with it, without going off my tree, I would also get a better response as she will see that she's not caused a commotion and we all get over it. If it becomes a big deal despite doing all these things, then you can always resort to incentives I guess, a sticker at the end of the day for big girls who use toilets.