To convince your kids to go back to wearing diapers get rid of all of the kids underwear.
Then put the kid in diapers yourself.
Discuss with the kids how much more comfortable diapers are and discuss the convenience of the diapers.
Keep telling the kids how easier it is to use diapers for pee and poop instead of wasting time going to the toilet.
With a diaper they can go potty anytime they want too and need too without having to hold it.
If your kid does not voluntarily wear the diaper you should make them wear it yourself.
After awhile they should get used to wearing diapers and decide they would rather wear them.
It takes time for the kid to get used to wearing diapers if they are not already a diaper lover.
Eventually your kid will most likely grow to love diapers.
Personally I would never potty train the kids to begin with and keep them in diapers.
If your kids are kept in diapers all the time and never potty trained then they will not need to be convinced to wear diapers again.