How to make a cancel button?

Hi, could somebody look at my code, because I have tried but it doesn't work and I have no clue on how to make the cancel button.Basically, if someone makes a booking, they are to able to click on the cancel button and clear their recorded that they have made. 

Could somebody help me please?

code Blocks.docx

image.docx

Does the other code work? Can you make a reservation OK?

 Try to get that working first. How are your listpickers initialized? It is not so nice to have the picked values in the listpicker itself. If I were you, I would add some labels to show these once picked. Then, when you cancel, you just reset the values in the labels.

Then, when you have that working, it is time to figure out what to do when the cancel button is pressed. I think that you are trying to reset a value in the tinyDB, but why are you having one?

Thanks I will try that.