Formula to add days to a date is not working - spreadsheet uploaded.

Hello,

I have a formula in Column N that should populate a date if column L is yes, it will take column M and add 182 days.

THis is the formula I have: =IF(AND(L6="Yes",ISNUMBER(M6)),M6+182,"")
I'm thinking the 'ISNUMBER' should be something different?
I'd like to have it also that if column L does not say 'yes' or is blank that column N stays blank - so formula only populates for those lines that say "yes" in column L...

Is that possible?

Thank you so much!