When pricing a general swap, the system uses the fixed leg’s frequency setting (as defined in the Payment Freq. dropdown list) to calculate this leg's payment periods.
Subsequently, in the Swap Cash Flow Dates window you can then edit the payment date for each of this leg's coupons individually in the Payment Date column.
By default each time you manually enter a payment date for a coupon in the Swap Cash Flow Dates window, the system automatically verifies that this date is valid in the context of the overall instrument definition. However, for a general swap’s fixed leg you can then optionally choose to allow yourself increased flexibility when defining the payment dates for the individual coupons.
You do this by instructing the system to only validate that the payment dates are sequential—in this mode, the system only ensures that a coupon’s payment date does not fall prior to the previous coupon’s payment date or after the next coupon’s payment date. In addition, it does not adjust a coupon's end date to match the payment date.
You activate this mode using the Control payment dates checkbox (as seen in Figure 1).
Once you have checked this checkbox, you can then, for example, set the payment dates for multiple coupons to the same date (as also seen in Figure 1).
Figure 1: Controlling the Payment Dates for a General Swap’s Fixed Leg