If they think about it then they will implement the system first and give the announcement after completing it. So most probably you won't get the time to convert your RP at previous rate. But freebitco should change few other thing as well if they set 2RP=1 sats. As example, in weekly lottery 1sats=2 tickets, decreasing the wager requirement for each reward point and lottery ticket. And few more changes. Even if you are frightened about the change your should convert your RP now.