I had a pastel female for the last two years who i fed mice to, and after I picked up more snakes this year i put her on f/t small rats and she took them with no problem. Some can be more picky, but some it is an easy switch.

I hope this change goes as easy for you as it did for me, she is pounding 80 gram rats every Tuesday, and she starts looking for them on Monday (i think she would eat every 4 days if I offered). Since the snake is already taking f/t i wouldn't think it would be too hard.