The THAW (Thaw Frozen Library) command changes the state of permanently frozen libraries and freeze-control libraries.
Syntax

Explanation
The THAW command changes the state of the specified permanently frozen and freeze-control libraries. Permanently frozen libraries are changed to temporary libraries. For freeze-control libraries, bit [27:1] in the LIBRARYSTATE task attribute of the library is reset and the EXECEPTIONEVENT task attribute results.
A permanently frozen library remains in the mix regardless of whether any users are attached to it.
A freeze-control library remains in the mix until it exits its control procedure when it becomes a temporary library.
A temporary library stays in the mix only as long as a user is attached to it.
Use the LIBS (Library Task Entries) command to display libraries and their mix numbers.
Example
2340 THAW