You can just swap them if it puts a player not in the desired position you want. The important is to be able to switch base formation fast enough in live matches. Swapping a player is something very fast to do, and as long as you not pressed saved, the undesired set-up will not take effect into the live match. So, (1) load formation, (2) swap players as needed and (3) click on save. This is much better than the pain of going to hold severals players one by one, move them to the desirednew position, then do substitutions, then save.
They can’t even get Associations right so this ain’t gonna happen.
ROMANBY VILLAGE FC (founded December 24th 2013)
Level 133
50 League
8 Champions/Elite League
4 Super League/Gold Cup
12 Cup
1 Super Cup