How badly did I mishandle this?
 

Frosh game. Server lets bad toss drop and then reserves (which, btw, she did without waiting for re-auth of the serve). A few points later, still serving (same term of service), she does it again. My R1 signals for re-serve.

As the R2, I gave a toot toot, invited myself across, while crossing I'm giving the "illegal serve" signal and telling him that that was the girl's second reserve during this term of service. He made the call, and we went on.

Just wondering how I properly should have handled this as R2. I'm assuming I shouldn't just let it go. But what should I do so that I'm not overstepping my authority or stepping on my R1?

I would be guilty of doing things like that as well not by intention but by reaction. I would say, it's my inadvertent whistle as it wasn't my authority to toot.

I don't think you're overstepping. If I see R1 signal for a second reserve, I'm going to whistle an officials' time out to discuss it with him. That way, I'm not making R1's call but we're not going blithely on either.

You handled it fine. What else could you do. You could not allow another re-serve. That's why we have R1 & R2 intea of just R1.

BITS, you did fine. Your partner made TWO errors however, not just starting to allow the second reserve. The first error was allowing the player to re-serve without a whistle and beckon following the toss and drop. Then, of course, the second error was in signaling a second re-serve during the same term of service. You did not overstep your boundaries by blowing your whistle and killing things before the second re-serve was allowed. Since you were aware of it, and I would hope that your scorekeeper was also, you had every right to blow the whistle for an illegal serve. Good job.