Registered Transferor is deceased, how does Executor act as Transferor…?

It’s not clear from the guidance, hence this question; in Panel 12 of TR1 it says the Transferor has to sign.  The registered property owner is deceased and the Executors are wishing to transfer the deeds.  They are also the Transferees.  
How please can the Executors sort this out?

TIA,

Stephen

Stephen - the Transferors are the Executors so they would have to execute the Transfer