A waiver of an inheritance can have many reasons. Potential heirs contractually agree to waive their compulsory share - often in return for a severance payment.
In return you waive your right to inheritance. You no longer have anything to do with the distribution of assets after the will has been opened, which must be handwritten. Once an inheritance waiver agreement has been signed, it can no longer be revoked. The only way to reverse it is with a termination agreement. However, an agreement must be reached between the testator and the renouncer. This must be certified again by a notary. Notaries usually charge double the fee for certifying a waiver of inheritance compared to the usual conditions. You can use the notary cost calculator on the Federal Chamber of Notaries website to find out how high the fees are. This depends on the amount of assets that are to be forgone. If compulsory heirs - whether with or without compensation - waive their share, this can of course make theribution of the remaining assets more relaxed.