How to use two accounts on the same phone?

[Bokeroneitor]

Good guys, I need your help I have a few days with an account level 25 now using pokefarmer, there have purchased an account level 31 in a forum,
works quite well but I wanted to ask you as I do to use both on the same phone, my account main level 25 is gmail, and the new level 31 is PTC can I switch between them?
I use pokefarmer in either or precautions should I take for it?
Thank you

 

[Bokeroneitor]

I think this is not going here, could you move?
Thank you.
Sry