After replacing the Crankshaft Position sensor, can I conduct the relearn without a scanner?

Nope, you must have a scan tool, here are the instructions. These are scan tools that can do the job from Amazon

https://amzn.to/3EeALoq

CKP SYSTEM VARIATION LEARN PROCEDURE

1. Install a scan tool.
2. Monitor the powertrain control module (PCM) for DTCs with a scan tool. If other DTCs are set, except DTC P0315, refer to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC Information.
3. Select the crankshaft position variation learn procedure with a scan tool.
4. The scan tool instructs you to perform the following:
1. Accelerate to wide open throttle (WOT).
2. Release throttle when fuel cut-off occurs.
3. Observe fuel cut-off for applicable engine.
4. Engine should not accelerate beyond calibrated RPM value.
5. Release throttle immediately if value is exceeded.
6. Block drive wheels.
7. Set parking brake.
8. DO NOT apply brake pedal.
9. Cycle ignition from OFF to ON.
10.Apply and hold brake pedal.
11.Start and idle engine.
12.Turn the A/C OFF.
13.Vehicle must remain in Park or Neutral.
14.The scan tool monitors certain component signals to determine if all the conditions are met to continue with the procedure. The scan tool only displays the condition that inhibits the procedure. The scan tool monitors the following components:
- Crankshaft position (CKP) sensor activity-If a CKP sensor condition occurs, refer to the applicable DTC.
- Camshaft position (CMP) signal activity-If a CMP signal condition occurs, refer to the applicable DTC.
- Engine coolant temperature (ECT)-If the engine coolant temperature is not warm enough, idle the engine until the engine coolant temperature reaches the correct temperature.
5. Enable the CKP system variation learn procedure with the scan tool and perform the following:
- Accelerate to WOT

IMPORTANT: While the learn procedure is in progress, release the throttle immediately when the engine starts to decelerate. The engine control is returned to the operator and the engine responds to throttle position after the learn procedure is complete.

- Release the throttle when fuel cut-off occurs
- Test in progress

6. The scan tool displays Learn Status: Learned this ignition. If the scan tool indicates that DTC P0315 ran and passed, the CKP variation learn procedure is complete. If the scan tool indicates DTC P0315 failed or did not run, refer to DTC P0315. If any other DTCs set, refer to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC Information.
7. Turn OFF the ignition for 30 seconds after the learn procedure is completed successfully.

The CKP system variation learn procedure is also required when the following service procedures have been performed, regardless of whether or not DTC P0315 is set:
- An engine replacement
- A PCM replacement
- A crankshaft balancer replacement
- A crankshaft replacement
- A CKP sensor replacement
- Any engine repairs which disturb the crankshaft to CKP sensor relationship

Please let us know what happens.