It's possible to define a relative date manually; this is not something that's commonly done. All relative dates start with the letter "R". This is then followed by:
D = days, W = weeks, M = months, Y = yearsW = start of week, w = end of week, M = start of month, m = end of month, Q = start of quarter, q = end of quarter, Y = start of year, y = end of year, F = start of fiscal year, f = end of fiscal yearExamples
RDM-15 decodes as "Relative", "Days", "Start of month", -15 = "Subtract fifteen days from the current date, then adjust to the beginning of that month."RWy+4 decodes as "Relative", "Weeks", "End of year", +4 = "Add four weeks to the current date then adjust to the end of that calendar year."RD30 decodes as "Relative", "Days", +30 = "Add thirty days to the current date."