Someone in my coop recently asked if SHs can exchange apts that are allocated the same # of shares and our attorney said no. You can't negotiate the difference in value of apts, and there are factors such as taxes, mortgages on the apts, etc. If this were allowed, SHs would be exchanging apts in their buildings and between buildings all the time, and what a mess that would be.

Your SH has to sell the shares for her apt and buy those for the other apt - and why does she want minimum paperwork due to her immigration status? Something there doesn't sound right to me.