Suppose I'm using an android phone running stock Android 6.0. Suppose further there are about 100 contacts and about 50 of them are with provider P and the rest is with provider G (as displayed by the default Google-Contacts app).
Now what I want to do is to move all the remaining 50 contacts which are still with G to P so I have every contact once and stored and synced with provider P.
How can I do this, preferably using only my phone?
Now I'd do this manually using the Contacts-App but it won't allow me change the storage provider for an established contact.
For clarification: the phone in question is a Nexus 5, provider G is obviously google using the device-default google account and provider P is posteo which is registered to Android as a "calendar service provider" via DAVDroid.