If your SAP is no longer reachable, you cannot get the follow up plan from any source, your SAP passed away (it happens!), your previous employer went out of business and took the follow up plan with them, then you can have a re-evaluation completed and a new follow up plan can be created for you so that you can move forward with the follow up plan and getting that completed. YOU MUST BE AT LEAST ON STEP 4 and the Determine Eligible for RTD test date has to be in the Clearinghouse already for this to be an option for you.
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Side note here:
If you are trying to change your SAP you will not be able to do so unless you call FMCSA and make the request -- normally if your SAP is responding to FMCSA and they have already entered the Initial Assessment Date (Step 3) then you will not normally see FMCSA remove a SAP.