How do you spell exorcise. For example to exorcise an agreement?

The correct spelling is exercise, meaning to act upon.

The man exercised at the gym.

John Smith exercised his right to request an attorney before being questioned by police.

Business owners of XYZ Electronics and ABC Television Repair exercised their agreement to combine their businesses into ABC-XYZ Electronics and Repair Services.

To exorcise is means to rid someone or something of (usually an evil spirit).