Once you have invoked the deities it is time for you to perform any rituals or magickal work and this could literally be anything. It all depends on what you have in mind – it doesn’t have to be spell-work. Having said that there are many, many spells which could be worked at this point and only you will know what it is you need to work on. Obviously you should have your spells ready prior to this.
It is important not to leave your circle until it has been uncast or dispersed. However, that is not to say that you are forbidden to leave it. Sometimes the need will arise, whether it’s a call of nature or something else entirely.
If you do need to leave the circle for any reason, you must first cut a “doorway.”
Standing in the east, take the athame and literally cut a doorway shape in the air. Walk through the doorway you have created in the Circle (taking the athame with you). Once you have exited the circle, turn and, facing the circle, use the athame to close the opening. This will seal the circle so that nothing can enter or leave while you are gone.
When you return to the circle, it is important that you follow the same procedure. Cut a doorway in the circle, step through, and close it again with the athame.