Change of position ?

How do I get this done ?
Since teams are bit off when this strict position min-max is put in force when the season start I would very much like to make ex. a guard to a center, or maybe a DE to DT. That must surely be possible
but I can't find out on what screen and how. Tried in the roster management but can't find anyhting.
The issue on changing a RB to FB, or TE to FB might also be important when these restriction forces you to do this.
Since teams are bit off when this strict position min-max is put in force when the season start I would very much like to make ex. a guard to a center, or maybe a DE to DT. That must surely be possible
but I can't find out on what screen and how. Tried in the roster management but can't find anyhting.
The issue on changing a RB to FB, or TE to FB might also be important when these restriction forces you to do this.