how can i change the knife damage?

i want it to be 700, possible?

Go to _damage.gsc. Find 1053 line.

[php]<...>

Callback_PlayerDamage_internal( eInflictor, eAttacker, victim, iDamage, iDFlags, sMeansOfDeath, sWeapon, vPoint, vDir, sHitLoc, psOffsetTime )
{
if((sMeansOfDeath == "MOD_MELEE") && !(isSubStr(sWeapon, "riotshield"))) {
iDamage = 700;
}

<...>[/php]

P.S.: Use search.

delete this in the code above
[php] && !(isSubStr(sWeapon, "riotshield"))[/php]
Edit: Didn't see the !