Call the programmer at 2 AM, whatever. Then hit Clear, and type the new application's transaction code. Internal Resources CICS transaction codes, program, and mapsets are the primary internal resources. As a user of CICS you will normally only be aware of the transaction codes. External Resources DB2 data bases and VSAM files, comprise the majority of External resources.
Some sequential resources exist, but are no longer common.
DB2 data bases do not follow any prescribed schedule. DB2 data is almost always available. VSAM files follow a prescribed schedule. The automatic close option can be different for each day of the week. Temporary changes to the availability schedule are permitted.