Hello and thank you for your question.
There is no 'special' procedure, you just need a conveyancer to do the sales/transfer documentation and you need to speak to the bank to get their approval for transfering your mortgage debt to your son.
HOWEVER, there are potentially very substantial tax implications and your son would have to pay duty on your property as if he were purchasing it for full value, tax he would not pay if he simply acquired the property upon your death. There may also be Capital Gains Tax implications and for these reasons you should discuss your options with an accountant before simply proceeding through a conveyancer.
Also, your bank may not accept any proposal to have your son take over the mortgage, and whilst they won't object to him paying the mortgage in your name, they may baulk at puting the mortgage in his name or allowing the transfer fo title unless the mortgage is discharged, in which case your son would have to arrange a new mortgage with a new bank and there would likely be substantial fees attached to setting up such a mortgage.
I trust the above assists your understanding as to what you need to check, even if it is not the news you likely were hoping for.
Good luck and PLEASE RATE MY ANSWER.