I assume it is hcl currently, disssolved in water. If it were base it woud have to be in a nonpolar solvet or alcohol or acetone. Assuming it's water you will add a base, I suppose until you have deprotonated it to base cocaine which isn't miscible with water, so you filter it out of the water, Dry it and dissolve it in acetone ether methanol or some other suitable solvent that dissolves the base and not the hcl, then you gas the mixture with HCL gas and cocaine hcl precipitates