Deed of variation

Hi All,

I am currently studying my advanced papers and this is my first post on the forum.

Can anyone please guide me on a question I have been asked:

In the will the husband leaves all his assets to the wife on IPDI, after she passes away all assets go into a discretionary trust for children/grandchildren.

They are asking if they can do a deed of variation to vary the assets on his death and utilise the residence nil rate band.

My understanding is if they can vary the will and ensure that his half of the main residence goes directly to the children on his death then yes the RNRB can be utilised, however I am not sure if this can be done legally?

Any help would be greatly appreciated

Regards

Gavin