Beth: "It's first and ten, with Daniels under center. And, it's an incomplete pass"

Color announcer: "They had two out wide and the tight end sneaking under the middle trying to take the robber off the slot route, really a great play design but they just couldn't connect on that one. Great coverage by #8 on the defense too."

Beth: "And now it's 2nd and ten, because we had an incomplete pass on that last play. And now they hand it off, and it doesn't go anywhere"

Color announcer: " Actually it looks like he may have got 3 or 4 yards there, lets see where they spot it. That was a good block by the center to open up the A-Gap here, and White just crashes on it. That would have been a touchdown if the linebacker didn't do his job, because you can see the safeties and corners are all chasing the curls on the sidelines. And now they spot it, yep, he got 4 yards"

Beth: "Here we go, it's 3rd down and, um, 6 yards. Daniels is back in a shotgun. And they pass it again, but it's incomplete. They are probably going to have to punt here. Daniels has just been struggling to complete his passes, and after all the hype around this game... [Daniels will go on to pass for 300 yds and 3 TD's in the game]"

Color announcer: "Yes Beth, looks like the punt unit is coming out. But don't count out Daniels. The receiver got a really good jump on the defender on that play, but then got tangled up right as Daniels had already committed to the throw. The defense is playing very well right now. "

TL;DR- Whoever is assigned the color announcer with Beth has two jobs to do.