An incorrect ownership share has been entered for my property. How can I correct this?

You should change your ownership share in your tax return. If you submit your tax return on paper, you should provide information on the actual ownership share under item 5.0 "Additional information". 

If you submit your tax return electronically, you must remember to tick the cause box for incorrect ownership share. Remember that this will entail a change to the tax returns of the other owners. You must be able to document any changes in ownership share.