Bypass locked sheets to change header

Hi Guys

I have a workbook with several locked sheets.

Each sheet has been setup with the same header which includes a company logo.

In order to change the logo / details to another company i need to go in and manually unlock, change, then relock all the sheets.

Can a macro be used which will bypass the locked sheets to access the header/footer options for all sheets so they can be changed in one go?

any help would be appreciated.

Many thanks

F