REB - Misdirection question

[aosquirrels]

Simple question.....

I use Red Elemetal Blast to counter a blue spell.  My opponent plays Misdirection and wants to change the target to my blue permanent.  My understanding is that REB is a modal spell and Misdirection can only change the target and not a mode of a spell. 

What's the call?

Thanks in advance for the answer.

[Apollyon]

You are correct. Since REB is modal, Misdirection changes the target of the REB to the only other legal target (I'm assuming the stack is "blue spell, REB, Misdirection", ordered from bottom to top): Misdirection.