Your contractor and your framers may be vastly different from mine, so this may have no relevance to your situation. But in my case, I found that contractor and framers were very helpful and willing to accommodate specific or even unusual requests so long as I could adequately explain or sketch what I wanted/needed and it didn't run afoul of code or good framing common sense.
What was more the limiting factors in my case were timing and communication. For example, perhaps I would notice a room or wall or floor or whatever nearing a certain point in construction which brought to attention a certain detail that would be helpful that perhaps I had not thought about until physically seeing that stage of progress. Before I could communicate a request cogently to my contractor and her in turn communicate that to framers, they had already passed that point. Sometimes were well beyond it.
That happened on one occasion in real time. We met with contractor at construction site to discuss a specific issue or two. I noticed walking around a minor detail that I wanted an opinion about whether to leave or change. We finished discussing what we were there for in a half hour or so. When done I brought up the other question, only to realize that while we were on one end of the house they had already framed substantially more on the other end and that question was now moot. No turning back. That happened in a half hour, and they weren't even working in that area when I made a mental note to ask later.
All that to say, framing happens fast. If there are specific requests, try your best to sit down and clearly go over them with contractor and framers before framing starts. Because once it does it's a blur. Mine were happy to work with me and be flexible, but sometimes what is already built is already built. We did move a wall a bit, closed a door in, moved a door, added accesses here and there. But some things are very difficult and expensive to undo to the point of being impractical.
The other limiting factor is material changes. Some requests may alter the length of a gluelam or lvl, or size of a member, and if already delivered to site it is a bigger cost hit to make that change. That only happened twice. Once I took the hit, once I didn't.