Key legal question
Whether the addendum validly changed the notice period to the statutory seven-day period during probation
Extracted holding
No. The wording 'according to CO' was too vague and could not reasonably be understood as a clear waiver of the originally agreed one-month notice period.
Extracted reasoning
Under the trust principle, termination clauses must be clear. In the absence of specific explanations, the clause was ambiguous and had to be interpreted against its author, the employer.