You can use the 'Reset' option from the Locals pull-down menu to clear out the model specifications for the current data set.
Selecting 'Reset' first changes the analysis, response, factors, classes, and model to '-NONE-'. Then, SAS/LAB software applies its intelligence to the data set. As a result, sometimes the value '-NONE-' may be replaced by an actual value.
If you have specified observation selection criteria to be applied to the data set, these criteria remain in effect even after a reset. Similarly, if you have specified a user-defined model for the data set, the user-defined model terms are not erased even though the model value has become '-NONE-'. These model terms will be used if you again specify 'User-defined model' for the model type.