Stamping appt unavailable can I enter US with B2 and apply change of status to H4

[Thanigaivel]

Primary applicant H1B Petition approved dependent H4 extension of stay applied not yet approved and current H4 expires in 10 days. Getting stamping schedule is hard in India. H4 dependent need to travel to India on emergency. Dependent is also having valid B2, if stamping appointment not available to stamp H4, can I return to US with B2 and apply change of status to H4 after reaching US once my extension of stay is approved.