Every day, as part of my job, people call me to fix their computers remotely.

After I answer the phone, I say something like, "Double-click the Remote Control on your desktop, and tell me when you see the prompt for a session key."

(The session key is a special code I tell them over the phone. After they enter it into the software, it lets me view their screen.)

The problem is that after I say, "tell me when you see the prompt for a session key," they say "Okay." and that "okay" can have two possible meanings:

#1: "Okay, I'll tell you when I get prompted to enter the session key." or
#2: "Okay, I see the session key prompt right now."

If they mean #2, I should give them the key as soon as I hear "okay." But if they mean #1, that means I should wait for them to ask me for the session key.

(Meaning #1 is by far the most common, but some folks know enough to launch the remote control app before they call me, so they want the session key right away.)

So my question, dear fellow wordies, is this:
How can I phrase the question such that their answer is unambiguous.

Any suggestions?