Inheritance Tax ,Canary Islands

Inheritance tax in the Canary Islands changed last year in that the 99 percent exemption for residents has been removed and tax on a sliding scale has to be paid. My wife is a non resident Spanish national who is due to inherit some valuable land on the death of her widowed mother.In to reduce her tax liability she wishes to know if her mother' s will can be amended to permit her to renounce in favour of her 2 children and 5 grandchildren thereby enabling them to take advantage of their individual tax exemptions in order to reduce the overall tax bill ?