If you are called to court as a witness and fail to attend the prosecution may ask the court to issue a witness summons against you. If you fail to attend in response to this you can be arrested and held in custody before being brought before the court. Although they are not generally in the business of having victims arrested the CPS will adopt this course if they believe your non-attendance will deny justice being done.It's really not a good idea to fail to attend if you are asked to do so.
Do you know if the CPS has "taken a view" on the matter since you changed your statement?