Verified answer

Change their routine slowly and explain to them what is happening (it will depend on how old the children are as to how much they will understand.)

You could have some activities relating to moving premises like books about moving house, or get the children to help you to rearrange the room so they understand what is involved in moving, lastly you could get the children to help you pack up ready to move and even make a special event out of moving day or the last day they're going to be there (if you're doing it on a day when the children aren't there.)

Hope this helps