How to convert Hundred Gig port on DellZ9100-ON switch to default configuration from a non-default config mode

Hi  ,

I am trying to split Hundred Gig port to quad port running at 25G speed.

When I issue the command "stack-unit 1 port 29 portmode quad speed 25G" it displays an error message "% Error: Quad mode cannot be changed on a port which has non-default config. Please verify whether the interface Hu 1/29  has default configs"

Could someone please provide steps to convert this port to default config in order to split the port  running in desired mode by user(quad/dual/single)?

Switch details:

Model:Z9100-ON

Dell Networking OS Version : 9.8(1.0P1)

Thanks,

Praveen