Most likely you will have shared copyright and therefore you will have to ask permission from your co-author(s) for everything you want to do with your material. You do not have to consider your co-author(s) when:
- Your work is part of a collective publication consisting of separate works that belong together and have been adjusted to each other, but are not indivisible. For example an article in a handbook.
- The contributions of the different authors can still be distinguished from each other.
If the publication is a collective, inseparable work, where the different contributions can no longer be distinguished, you will always need permission from all the creators to use the publication for any specific use.