In case the order has been placed with an already active mandate, SIP will be regularized in T+14 days. In case the order has been placed with a new Bank Mandate, you can safely expect the SIP to be regularized by the next debit date. Usually, a new mandate takes 15-20 days to get approved by banks. This turn around time also depends on the efficiency of your bank, some banks respond quickly whereas bank like SBI usually takes T+30 days to approve a bank mandate. In case you have missed a SIP, you can simply make a order of additional investment from the platform to compensate it.