planning permission granted now mrs changed her mind

have had planning granted for attached garage garage in our rear yard but after clearing the site the wife would like to make it a garage /garden room
this would entail changing roof from grey sheeting to clear and the rear 8ft from wall and upvc door to smaller wall and upvc French or patio doors
will I have to resubmit or just change them the only thing anyone would see is the roof

as it is built upto 3 boundaries building regs is needed so would the above still be possible

It is often possible to do minor alterations to existing plans/permission at no cost. You will need to submit an original plan and another with your required minor alterations clearly shown.

The only way you'll know if this will be allowed is to ask. A telephone call should suffice and they'll tell you the procedure.

Having been through the process myself and wanting to change agreed plans, the best people to ask is the planning dept of your LA.

Tell them what you have been given permission for, what you want to change and ask them what they want you to do.

It will either be minor amendment (doubtful as it seems you want to do more that this) or a new application.