While travelling to PA, i was issued a ticket in PA for speeeding 85 on a 65 mph highways. I'm holding WA driver license.

Check with the WA State MV agency before you resolve the PA summons, to determine what actions they will take in regards to your license. The violation will be reported by PA to WA, and under certain circumstances (at least here in NJ) certain types of additional consequences have applied for the out-of-state violation. Getting a guilty plea reversed after WA decides to take action on your license is not a certain prospect, not to mention that it is not cheap. Good luck.

DISCLAIMER I do not practice law in your State. This answer is provided solely for informational purposes only. This answer does not constitute legal advice, create an attorney-client relationship, or constitute attorney advertising.