According to The Telegraph:
The NHS is to launch its first ever service for transgender patients wanting to return to the gender of their birth.
The move comes in the wake of the Cass Review, an independent report into transgender services, which found that children were being hurried down “affirmative” pathways involving powerful drugs and medical interventions.
Known as the 'boomerang' service, this ensures that people who used the previous service to change their gender from that of their birth can use the new service to change it back again after they change their mind.
It's all very confusing.