The contract documents shall contain the basis upon which time extensions may be granted. Substantiating data must be submitted with the requests for extensions. Such time extensions, if justified, shall be granted by Change Order only. It is important that written notices of delay be submitted to the design consultant within twenty days of the delay. Time extensions for changes in the work must be included on the Change Order form authorizing such change.
Okla. Admin. Code § 260:65-1-17