#include<bits/stdc++.h>
using namespace std;
int t,n,m,k,cnt,cc;
char a[105][105],tmp[105][105];
struct node{int x,y;}v[100005];
char p[2]={'B','W'};
void output()
{
    cout<<"YES\n";
    for(int i=1;i<=n;i++,cout<<"\n")
        for(int j=1;j<=m;j++) cout<<tmp[i][j];
}
char check(int x,int y)
{
    cc++;
    char ans1='?',ans2='?',ans3='?',ans4='?';
    // cout<<"xsa";
    // cout<<ans1<<" "<<ans2<<" "<<ans3<<" "<<ans4<<"\n";
    if(x>1&&y>1&&tmp[x-1][y-1]=='B'&&tmp[x-1][y]=='W'&&tmp[x][y-1]=='W') ans1='B';
    else if(x>1&&y>1&&tmp[x-1][y-1]=='W'&&tmp[x-1][y]=='B'&&tmp[x][y-1]=='B') ans1='W';
    else ans1='?';
    if(x>1&&y<m&&tmp[x-1][y]=='B'&&tmp[x-1][y+1]=='W'&&tmp[x][y+1]=='B') ans2='W';
    else if(x>1&&y<m&&tmp[x-1][y]=='W'&&tmp[x-1][y+1]=='B'&&tmp[x][y+1]=='W') ans2='B';
    else ans2='?';
    if(x<n&&y>1&&tmp[x][y-1]=='B'&&tmp[x+1][y-1]=='W'&&tmp[x+1][y]=='B') ans3='W';
    else if(x>1&&y<m&&tmp[x][y-1]=='W'&&tmp[x+1][y-1]=='B'&&tmp[x+1][y]=='W') ans3='B';
    else ans3='?';
    if(x<n&&y<m&&tmp[x+1][y+1]=='B'&&tmp[x+1][y]=='W'&&tmp[x][y+1]=='W') ans4='B';
    else if(x<n&&y<m&&tmp[x+1][y+1]=='W'&&tmp[x+1][y]=='B'&&tmp[x][y+1]=='B') ans4='W';
    else ans4='?';
    if(ans1=='?'&&ans2=='?'&&ans3=='?'&&ans4=='?') return '?';
    else if(ans1!='B'&&ans2!='B'&&ans3!='B'&&ans4!='B') return 'B';
    else if(ans1!='W'&&ans2!='W'&&ans3!='W'&&ans4!='W') return 'W';
    else return '!';
}
bool cmp1(node a,node b){return a.x+a.y<b.x+b.y;}
bool cmp2(node a,node b){return a.x+a.y>b.x+b.y;}
bool cmp3(node a,node b){return a.x-a.y<b.x-b.y;}
bool cmp4(node a,node b){return a.x-a.y>b.x-b.y;}
int main()
{
    // freopen("a.in","r",stdin);
    // freopen("a.out","w",stdout);
    ios::sync_with_stdio(0);
    cin.tie(0);cout.tie(0);
    cin>>t;
    for(int l=1;l<=t;l++)
    {
        cin>>n>>m;
        cnt=0;
        for(int i=1;i<=n;i++)
            for(int j=1;j<=m;j++)
            {
                cin>>a[i][j];
                if(a[i][j]=='?') v[++cnt]={i,j};
            }
        for(int i=1;i<=n;i++) for(int j=1;j<=m;j++) tmp[i][j]=a[i][j];
        int flag=0;
        sort(v+1,v+cnt+1,cmp1);
        for(int i=1;i<=cnt;i++)
        {
            if(check(v[i].x,v[i].y)!='?'&&check(v[i].x,v[i].y)!='!') tmp[v[i].x][v[i].y]=a[v[i].x][v[i].y]=check(v[i].x,v[i].y);
            else continue;
        }
        sort(v+1,v+cnt+1,cmp2);
        for(int i=1;i<=cnt;i++)
        {
            if(check(v[i].x,v[i].y)!='?'&&check(v[i].x,v[i].y)!='!') tmp[v[i].x][v[i].y]=a[v[i].x][v[i].y]=check(v[i].x,v[i].y);
            else continue;
        }
        sort(v+1,v+cnt+1,cmp3);
        for(int i=1;i<=cnt;i++)
        {
            if(check(v[i].x,v[i].y)!='?'&&check(v[i].x,v[i].y)!='!') tmp[v[i].x][v[i].y]=a[v[i].x][v[i].y]=check(v[i].x,v[i].y);
            else continue;
        }
        sort(v+1,v+cnt+1,cmp4);
        for(int i=1;i<=cnt;i++)
        {
            if(check(v[i].x,v[i].y)!='?'&&check(v[i].x,v[i].y)!='!') tmp[v[i].x][v[i].y]=a[v[i].x][v[i].y]=check(v[i].x,v[i].y);
            else continue;
        }
        cnt=0;
        for(int i=1;i<=n;i++)
            for(int j=1;j<=m;j++) if(a[i][j]=='?') v[++cnt]={i,j};
        for(int c=1;c<=800&&flag==0;c++)
        {
            for(int i=1;i<=n;i++) for(int j=1;j<=m;j++) tmp[i][j]=a[i][j];
            for(int i=1;i<=cnt;i++)
            {
                if(tmp[v[i].x][v[i].y]!='?') continue;
                int f=0;
                char ans=check(v[i].x,v[i].y);
                if(ans=='!'){tmp[v[i].x][v[i].y]='B';break;}
                if(ans=='?') tmp[v[i].x][v[i].y]=p[rand()&1];
                else tmp[v[i].x][v[i].y]=ans;
            }
            int f=0;
            for(int i=1;i<n;i++)
                for(int j=1;j<m;j++)
                    if(tmp[i][j]==tmp[i+1][j+1]&&tmp[i][j+1]==tmp[i+1][j]&&tmp[i][j]!=tmp[i][j+1]) f=1;
            if(f==1) continue;
            flag=1;
            output();
            break;
        }
        if(flag==0) cout<<"NO\n";
    }
    // cout<<cc<<"\n";
}
/*
5
2 6
??????
W???B?
2 6
??????
W???B?
2 6
??????
W???B?
5 10
?WW????W??
BW?W???WBW
BW??WB????
???W??????
?W????B???
5 10
?WW????W??
BW?W???WBW
BW??WB????
???W??????
?W????B???
*/