So i've got an old acoustic guitar and i want to change the strings, but lacks those bridge pins. Is there any chance to change the bridge or to change the strings with this kind of bridge?

it's a pain in the ass to change a bridge, and would cot more than the guitar.

Changing strings is easy. You just have to tie them. Nylon strings right? It looks like a classical guitar.
Winner of the 2011 Virginia Guitar Festival

Protools HD
Lynx Aurora 16/HD192
Mojave, Sennheiser, AKG, EV etc mics
Focusrite ISA828 pres
Waves Mercury
Random Rack Gear

65 Deluxe Reverb
American Standard Strat
Taylor 712
Actually i was undecided between nylon or steel strings, but i searched that out and apparently its better nylon or i would break guitar in half... Thanks.