In absolute quantification using the standard curve method, you quantitate unknowns based on a known quantity. First you create a standard curve; then you compare unknowns to the standard curve and extrapolate a value.
In relative quantification, you analyze changes in gene expression in a given sample relative to another reference sample.
More info about relative standard curve you can find here:
So, when we are doing relative quantification using standard curve, should we put the standard curve serial dilution in every run along with unknown samples?