Tds returns without pan number

Hi,

We have an issue while filing the TDS returns.One of our clients did not collect the TDS from their previous landlord (they moved to new office now) and paid full amount as the rent. But, after they came to know about the TDS deduction, they paid 10% of their rent as TDS with penalty. Now, their issue is, how to file the TDS returns without previous landlord's PAN number (he is not willing to give the PAN number). Please help us. Thanks in advance.

regards,

Prasad