how to partially scale a 2 d object?

I have a irregular 2d object.
In the scale tool, i can only scale the whole object.
what if i want to scale , for example, the center part of the 2d object by 10mm?

You should be able to scale any single line or other entity of a drawing. If not maybe it has been made a block. You have to "Explode" it then (Modify - Explode).