NTPs are shipped the following business day, unless otherwise stated. Changes or additions may be made to your order until the time of shipping, which is 3pm PST. For oligonucleotide or custom compound orders, if we can pull the order out of production before synthesis is started, we can accommodate your request without incurring an extra fee. However, once synthesis of the product has begun, changes to the sequence or scale are no longer possible unless costs of the current synthesis are met. Please keep in mind that you may be responsible for the cost of any specialized reagents that were purchased to synthesize your compound, plus a 10% surcharge. PAGE or HPLC purification may be added anytime before an oligonucleotide is shipped.