Your opportunity here will depend on your SAS experience level - to start.
Investigate using PROC IMPORT to read your Excel file and create a SAS data library member - here is a Google advanced search argument against the SAS.COM site for DOC and supplemental technical/conference reference material on the topic:
import excel file site:sas.com
Then after you have a SAS member, you will need to compose a SAS program to read your SAS member iteratively for each "date" using a WHERE statement and generate a separate SAS file for each date and export the selected data to a new (and uniquely named) Excel file -- here is a Google advanced search argument against the SAS.COM site for DOC and supplemental technical/conference reference material on the topic:
generate sas code site:sas.com
Within these DOC/website technical referencs below, you will see various options to choose, from PROC SQL using " INTO " and also using CALL EXECUTE to generate your SAS code for subsequent execution, either as a macro call/execution or as DATA and/or PROC step execution code.
Suggest you start with the DOC references below, develop a working program that reads and writes a single file, and then come back to the forum for input/feedback about how you can take that program and turn it into something that will be executed multiple times based on your input data "date" values.
Scott Barry
SBBWorks, Inc.
SAS Macro Language: Reference, Introduction to the Macro Facility
http://support.sas.com/documentation/cdl/en/mcrolref/61885/HTML/default/a002293969.htm
SAS Macro Programming for Beginners
Susan J. Slaughter, Avocet Solutions, Davis, CA
Lora D. Delwiche, Delwiche Consulting, Winters, CA
http://www2.sas.com/proceedings/sugi29/243-29.pdf
Intermediate and Advanced SAS Macros
Steven First, Katie Ronk, Systems Seminar Consultants, Madison, WI
http://www2.sas.com/proceedings/sugi31/107-31.pdf