I have a list of tenants and the dates they moved in and out of their flats.
I need to show which weeks within a specific period that the flats were
filled - either by showing the tenants intials or a tick.

A B C D E
F G H
Unit No Client Start End 04-01 11-01 18-01 25-01
1 JB 23-11 06-02 JB
2 GK 05-01 GK GK GK GK
3 LB 01-12 28-02 LB LB LB LB

Does anybody know how is best to do this? We've tried using an IF formula
but it doesn't work if their is a start and end date.