I haven't dealt with ISO2859, but it appears that ISO2859 = MIL-STD-105E = ANSI/ASQ Z1.4.
In that case, you certainly CANNOT just change AC to 0. By simply lowering the acceptance number, you are increasing the risk of accepting a bad lot. If you want to start with ISO2859 = MIL-STD-105E = ANSI/ASQ Z1.4, my personally opinion would be to choose the AQL you are comfortable with, then find the sample size at that AQL which already uses AC=0. This may well mean sampling few pieces than suggested by the plan, but it puts the alpha and beta risk at least in the right general range for your AQL.
Tim F