I have looked in the wiki and the guide, but have not found any explanation on how to leave a kingdom I do not like.

I am aware (because of the page upon logging in), that you can apply to a kingdom that is seeking a new province and that you might get an invitation. There used to be a 'defect' option as well, but I have searched and not found any method of doing that.

If I get an invitation, or if someone tells me how to defect, what are the requirements to go through with it?

Can I defect/accept an invitation if I have recently run aggressive/tm ops?
If I have troops in training?
If I have buildings in construction?
If I do change kingdoms while training/building, will I lose them?
Is there any land loss in moving to a new kingdom?
Is there anything else I should know about changing kingdoms?

Thanks to any who take the time to read and respond to this.