This is kind of a confusing way to go about getting advice.
First - chances are, you're overthinking this. Want to know the easiest and most efficient way to do a switch/reset a trick when walking between groups or tables? Just .... switch the cards or reset the trick. Literally, just do it, as you walk over to the table or when you first get there, while casually chatting with the people. If you have a card in your pocket you need to switch for a card in the deck, just do that. Take the card from your pocket, put it where it goes, take the card out of the deck and put it where it needs to be. If you don't make a big deal out of it, no one will ever notice.
Second - If you really want a specific description, then give us a detailed description of what you're trying to do. Where are the cards going to be when you are doing this? Where do they need to be? What are the restrictions?
Quick story: I used to do a version of Chicago opener as the third trick in a set of card tricks while busking. To do this version I literally handed the deck to an audience member, turned my back, and asked them to go through the deck face up and pick one out. When they had picked one, I asked them to put the rest of the deck face down in my hand, which I held out behind me. While they were doing that, with my back to them, I would take the necessary cards to set up the trick out of my shirt pocket, cop them, and wait until they gave me back the deck at which time I'd add the copped cards to the bottom of the deck and do the trick. It's a great way to do that, because by the time this rolled around, everyone had seen every card and handled the deck, so when the odd color was shown it was very surprising. Anyway, one time I'm doing this routine, and I turn around to let them select the card and there's a dude standing not 8 feet from me, staring right at me. I smiled and waved to him, said something like, "Hey, what's up? You get a better view over there (While gesturing over my shoulder to the majority of the crowd)". While I said that, I reached up to my pocket, copped the cards I needed right in front of this guy, and went on with the routine like nothing was out of the ordinary. He came around to the front and was just as amazed as anyone else in the crowd, even though I had literally prepped for it right in front of him.
A casual attitude and confidence go a long way.
