Date difference in work manager 6.1

Hi expert,

does anybody know how to get date difference. I am new to work manager. The requirement is like you have client entered date & system date the difference of this two should not be greater than 24 hour.

for example

client entered  date - 15.01.2015 23:38 PM

system date - 16.01.2015 00:26 AM

here the diff is greater than 24hour.

please tell me how can I compare this in agentry?

Thanks in Adv