Depending on the type of covering it can be quite simple,

Get out your covering iron and heat it up, make a hole in the covering and use the iron to warm the covering around it. Gently pull the covering off of the AC warming the covering as you go.

The idea being, the glue is heat activated - warming it up loosens it for both shrinking and removal.

However; depending on the type of covering, you can have bits & pieces of colouring left behind, and/or small pieces of covering that will have to be removed carefully.

PLUS; it's quite likely the plane will now be 'sticky' (this will happen no matter how you remove the covering)- a residue from the glue, no problems it just makes the new covering job a little 'different.'

Good Luck!!