Hi,

There is a few ways to create new or extend a tour

1. If this is just an extension of your existing tour ie: Sunset Cruise (Wednesday to Saturday) SUMMER

 

You can update the date restrictions to now include Sunday:

 

 

 

Then in your daily rates, you will be able to stop sell all Sundays excluding January.

Then Enable Stop sells through January:

You will then need to update the tour name" Sunset Cruise (Wednesday to Saturday) SUMMER "

Alternately, you can copy and create a new tour just for sundays:

Then complete the process above.