Is it possible to change a characters skin/model with another?

[trueshothaze]

I vaguely remember reading about this somewhere but I don't know if this applies to games on the emulator.

Opinions?

Game doesn't matter, just questioning if it's possible to do this.

EDIT: Also, Cheat Engine 6.2, I want to scan and find the address for in-game countdown timers.
I read somewhere that I should use the "unknown initial value" and then ""decreased value" but I don't know where those features are.

EDIT: Okay, I found the countdown timer it was rather easy. But, a new problem arose. Even though I was able to freeze the timer in Cheat Engine it still gives me a warning that the timer is almost up and that I better get back before time is up. I tested this, and again even though I was able to find and freeze the timer, it still gave me that warning, and as if the timer didn't stop I lost at the mini-game.
I even replaced with code that does nothing, but that did not work either. So, what else can I do that will let me roam around picking up all the goodies before the invisible timer runs out?

[PyroBunta]

I remember there being some codes for changing character models for RE4 and some games, but as for modifying character skins (like say, GTA: San Andreas) you'll have to manually modify the game's data itself instead of using only codes.

[trueshothaze]

I remember there being some codes for changing character models for RE4 and some games, but as for modifying character skins (like say, GTA: San Andreas) you'll have to manually modify the game's data itself instead of using only codes.

Thanks.