Yes. You do not have to remain in part-time or full-time training for the entire training program. In fact, many registrars switch between full-time and part-time training, typically due to family or health reasons.
The AGPT program and GPTQ are very flexible when it comes to allowing changes in training status.
In full-time training, you train for a minimum of 38 hours per week. In part-time training, you train for a minimum of 14.5 hours a week.