Quote From CalvinPlummer:
I'm currently half way through my PhD with just over 2 years to go.
A part time job opportunity has come up which would seriously benefit my career. However it's only for 2 years.
If I switch to a part time PhD that will effectively double my time left to 4 years but the job contract is just for 2 of those.
Is it ever possible to go back to full time after switching to PT?
You can ask your supervisor but I do not think it is a good idea to do this. If you are paid in your PhD enough to pay your rent and bills just go forward and finish in two years.