Hey,
my little girl is 4, and we have same problems. She has been potty trained when she was 2 and did very well for a while.You know, I notices that she is just not wanting to go cause she feels like she looses something when she need to take a potty break.
I think it is important to understand a child`s motivation. If he has a physical problem, that`s a different story. (he is five, give it one more year, that`s what I was told)
BUT! If it is just being too busy and simply not willing to take a break then there`s some things ot do. I keep it in mind not to ever humiliate her, but teach her that wetting panties is not right
What we did, is that after we had wet panties we told her, that the next day it is going to be a day, when she`ll be send to the potty any time mommy thinks so. Since she is -apparently- not willing to take a break, and "doesn`t feel it", then I will help her. So I send her to the potty a LOT! I made her sit even though she didn`t want to. That make her feel uncomfortable, cause she had to go a lot, and she of course doesn`t want that! And I reminded her for the whole time that it is important for you to remember, then mommy doesn`t need to help you this way, this many times. I sent her when she was in the middle of playing, or something fun, and explained, that she won`t miss out on anything, but saves us wet panties and rashes.
Then, there came a time when I just asked her often, if she needs to go to the bathroom. I would take her, look at her and ask. That might work for you as well.
By the way she always tells me no (most of the time) and then she wets her panties. Well, I punish her for that, cause I consider this lying, she is too smart not to know when she needs to go and she is even asked!
And, what also works I think, at least with her is to tell her about how "big girls" act, and she always wants to be a big girl, and act that way. Maybe that`ll be a motivation for your child too.
Well, I don`t know if this helps, but maybe.
H.