Silo 3d make planar problem

hi dear silo followers.i am new to silo software.currenty i ve been using max and as u may know there is a function in it such as make planar so that i can make any polygon from the all sides smooth.as u see in the picture i have to make that back polygon smooth.is there any way or can u guide me in silo?

Try Flatten in the Modify menu.

Select Modify  - Opts to choose world xyz / local xyx / selection normal

thank u my friend.worked very well.