V4MD suggest for a undo button

[info at vallemediatime.com]

Hi Ruslan and list,
I need to add a "undo" button for return immediatly at previous saved record, somebody can suggest me a good way in Valentina?

eg 
Rec1
1. In myStringField I type: "John"
2. I click on updateRecord button and write rec1 into disk
3. In the same record and same field I type another name "Bill"
4. I click on updateRecord button and write rec1 into disk again
5. I click on undo button and I return to see "John" in myStringField... how?

Thanks
Paolo