router dhcp and forced IP re-assignment

my linksys wrt54g router has a dhcp server which i am using.

it gives me the abilitiy to delete its table entries but no ability to
reconstruct the table by forcing the leases to renew.

The DHCP server has the capability. I define the lease period.
Theoretically I could redefine the lease to one minute and wait
two minutes and lo and behold i would have my table re-generated.

No such luck.

Is there a good reason why linksys could not reconstruct the
dhcp table after i had deleted the entries?

Thank you,
Bil