You would like to edit the contract period or delete the contract, but it's not working? You will likely see the following message:
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You can adjust the contract period or delete the contract if you remove all the mutations. There are three spots where you can encounter mutations, under salaries, workweek and contract settings.

You have to remove the mutations under every category if you want to be able to adjust the contract period or delete the contract.

If you have done that, the 'delete' button will appear again and you can adjust the contract period too.